About Zener (twitter: @kerrichal)


Ludum Dare 37
Ludum Dare 34
Ludum Dare 32
Ludum Dare 28
Ludum Dare 27
Ludum Dare 26
Ludum Dare 25
Ludum Dare 24
Ludum Dare 23

Zener's Trophies

Zener's Archive

Progress (and name)

Posted by (twitter: @kerrichal)
Sunday, April 19th, 2015 1:03 pm


after two ludums I’m back into the competition, again as a one team army. I decided to name my game Gravitron, as the unconventional weapon is a gravity weapon. Using Unity, Monodevelop, Paint shop Pro and Tilestudio. For the sounds I will use something generated  (http://www.anticulture.net/MusicGenerators.php) + synth sounds.






Mother Love Postmortem

Posted by (twitter: @kerrichal)
Thursday, December 26th, 2013 3:48 am


I got back to the 48h competition and this time I had the courage to participate using Unity3D for the first time, all my previous entries were done in Flash/AS3. The idea for the theme came from mixing the fact that  there is only one mother and an egg-and-spoon race. At the end you carry your child on the mouth and at the same time you can kill enemies throwing it, but after that it becomes vulnerable. I didn’t like the idea of using human like characters and I decided to use some cute japanese like characters.

Link to Mother Love

What went right


I lack 3d modelling skills and 2d gives me more freedom, at least in the art oprions. I decided to use Unity this time mainly due to the release of the 2D Tools. And they are very good indeed, importing and using sprites is very easy, also adding animations is pretty straightforward. I’m not surprised so many Ludum Dare entries are done in Unity these days.


2D.5 playfield

This comes too from the fact that Unity is a 3D engine, adding the third dimension gives the game a modern look and you don’t need to program parallax scrolls anymore. Special mention for the 3D tress, they make the oeverall quality go up :).


For some people the game is too easy but others have some trouble with the water zone. A checkpoint in the middle of the stage put things easier.

The Baby

He’s cute and needs protection, cries when his mother is not with him…well…it’s a lot better than a rock or any other kind of weapon.


What went wrong


Unity allows you to get something working very fast but you don’t have full control of the game and there are times when you are stuck trying to fix something or make something work the way you intend.

Moving platforms

This was one these occasions where I couldn’t get Unity to work the way I wanted, fixing one thing broke the other and so. At he end you don’t move along with the moving platform, but it was the least bad option.

Wrong weekend

Company dinner, family lunch, electricity cuts in the first world… a lot of circumstances that left me with half the time to develop my entry. I’m very happy with it nevertheless.

Jump & Run Game: Mother Love

Posted by (twitter: @kerrichal)
Sunday, December 15th, 2013 4:56 pm

Despite all the troubles of this weekend I managed to finish this little game. Enjoy!



There is only one mother…

Posted by (twitter: @kerrichal)
Saturday, December 14th, 2013 5:44 pm

Yes, this is the idea behind the game I’m working on for this Ludum Dare. You take the role of a strange creature that must take care of her child carriying it on her mouth but at the same time she can spit her child to kill some enemies. It’s a bit bizzarre but here are my first steps:


And this time I finally had the courage to do it in Unity…


And then it evolved!

Posted by (twitter: @kerrichal)
Sunday, August 25th, 2013 3:23 pm

End of the second day and we have the two parts of the game almost finished. Tomorrow play, tune and debug!



First day is over: welcome Bob

Posted by (twitter: @kerrichal)
Saturday, August 24th, 2013 4:54 pm

After a lot of pizzas and learning a bit of Flixel the day is over.


Please meet Bob, our main character (the one below)


First steps

Posted by (twitter: @kerrichal)
Saturday, August 24th, 2013 7:25 am

The four of us had a productive breakfast meeting and now we have the idea for the game: It’s about a fearless mutated creature that needs to kill. The first tiles, player, UI tests are done, now it’s time to get serious!


Ludum27And we are:

  • Lady Cerberus (Artist)
  • Algerator (Coder)
  • MALHCat (Coder)
  • Zener (Coder)


We are in!

Posted by (twitter: @kerrichal)
Friday, August 23rd, 2013 5:03 am

This time I will be part of a team and we will participate on the Jam Compo. At the moment it’s four os us, three programmers and one artist. An artist, this is luxury!

We will be using Flash most probably, maybe even Unity if we find a concept that works best in 3D. Flixel sounds like a candidate to use for the Flash engine, but it’s not yet decided.

For graphics Photoshop and Flash are most likely to be used and for sound some sfx generators that are widely available.

It’s going to be fun as hell!


Minimal Annihilation Postmortem

Posted by (twitter: @kerrichal)
Thursday, May 16th, 2013 1:58 pm

Minimalism is not easy, with just 48h feels like anything you could do should be minimalistic by nature. I usually waste half a day at least to get a good idea but this time the idea come up quite early, a simplified strategy game. It is one of my favourite genres and I thought it would be funny to do. And it was very fun indeed :)

Link to Minimal Annihilation


The concept


The inspiration came from many places, a quick list:

  • Shadez: A game I played long time ago that consisted in building units using a cooldown system to the enemy. It had no building and the view was a lateral scroll.
  • Starcraft and Dune 2: I wanted the player to feel like in Starcraft, and many elements of the game are borrowed from the Blizzard game. Resource gathering, building, unit training.
  • 8-bit Starcraft video: A fake video that appeared some time ago in youtube, I really loved it. A pity we never had this one 30 years ago.
  • And even more inspiration from my childhood, like the Dr Who droids for the drones, the Turrican armor for the soldiers and the Starcom set of toys for the rest on units.

What went right

The idea

I have never played an strategy game with these game mechanics, and there was the risk that the game wasn’t funny after all or that the game mechanics didn’t work when put together. The task of setting up unit behaviour, movement, etc for this game take a long time, almost a day and a half without knowing if the idea would work, but at the end the feeling was what I expected

The graphic style

I’m not a graphician and I feel I’m not good at it. In my last Ludum Dare I spent many time doing graphics, and for this game I needed all the time to program a proper RTS. Thanks to the theme I could go for black & white graphics, they ended looking very “Apple like”. Another good decision was to scale them by 3X, allowing me to draw all the graphics using pixel art style. I’m not so bad at pixel art because I spent many hours as a kid playing with Deluxe Paint on Amiga, for fun and for some freeware games. The UI ended being quite good and big at the end, and the minimap works, although nobody has noticed it I think.



For the scope of the game I needed a language I am comfortable with, and again I decided Flash/AS3 would be the best to code the game fast. I still want to try to use Unity3D for Ludum Dare, but it will be in another occasion. And I wanted to use Flash to publish the game in a web browser.


Very little time left to submit the entry, I’m very tired. I take a look at my todo list and I read “particles”. I thought “Yeah, they would be cool when a unit dies, but I have no time for almost anything”. And then I coded the most minimalistic particle loop I could imagine, I just needed the particles to move, to detect the ground and to die.

And they were done using just five lines of code, these ones:

x += dx;
y += dy;

dy += 0.015;

if (y >= Game.GROUND_Y) dy = -dy*0.7;


Fool of me, I only used them when a unit dies. I could have used them to indicate that the droids are mining or when a unit is firing, but my mind was running out of fuel as I said.

It has sound!

Yes, it is my first entry with sound. I lack any musician abilities, but I have seen other people using tools like Autotracker to generate the sound and I decided to try to include some sound in the game this time. I had also downloaded a synthesizer tool to add some sound effects but at the end I only used one sfx for the clicking.

What went wrong

No right click

I was very happy on day one, the controls could be like in Starcraft: left click for select, right click for action, excellent. But then I remembered I wanted to distribute it via web, and Flash only allows the right click on AIR applications, (facepalm). I had to spent time patching all the code to make the left click behave in a different way depending on the different situations and it turned out to be quite difficult. The result, sometimes after you have done something with a drone and click on another unit, the drones move to that unit, losing the last action, usually mining minerals.

Nasty animation engine

At some point I had to deal with the unit animations, and the solution I implemented was quite basic, there was not much time to do a proper animation system from scratch. The result is that any new unit required to copy&paste several lines to load the graphics and create the images for both factions. The most tedious and boring task to do while developing the game is this one for sure.


One of the trickiest parts to implement. The AI is not very clever, at least knows how to get resources and to build everything. It can be a challenge to the player, but when the player knows how to win I think it is easy to win. Basically how it works is calculating its status and the oponent status and then acting based on its needs. Pretty basic but it does the work.


Lack of time

This is quite normal after all, milestones suck. I had a lot of things I wanted to add, like a proper tutorial, more sound effects, more builds, more types of units, add a repair option. The unit balancing is was iterated many times but still need a lot of tuning, I am glad (and surprised) that several people has asked for a final version of the game. I can do that, should be easier with plenty of time available :)


My scope for the game was too big, event a minimalistic scale and I had a hard time trying to implement everything I had in mind. But at the end I managed to get a full mini game, and I think that most RTS fan will find it very enjoyable. For next Ludum I hope to do something simpler, this way I will have time to focus in the sound or in doing something with Unity. But anyway I am very happy for having implemented a mini-Starcraft in 48h!

Almost there!

Posted by (twitter: @kerrichal)
Sunday, April 28th, 2013 1:17 pm

A lot of polishing still left.28_afternoon

Second day starts!

Posted by (twitter: @kerrichal)
Sunday, April 28th, 2013 2:14 am


Now it’s time to bring insome violence to the game. A lot of work still needs to be done.

Minimal Annihilation: WIP

Posted by (twitter: @kerrichal)
Saturday, April 27th, 2013 9:07 am

I have most of the basic stuff running: Scroll, zoom, select units, fillbars, …

I think it’s time to add some basic HUD and start doing the gameplay


Let’s start!

Posted by (twitter: @kerrichal)
Friday, April 26th, 2013 11:49 pm

I have an idea, let’s see if I have time to code it ^^


Evil Cat Post-mortem

Posted by (twitter: @kerrichal)
Tuesday, January 1st, 2013 6:26 am

This is the third consecutive Ludum Dare where I have participated and Evil Cat is easily my best entry so far. When I started coding I was not very confident that I could end up having something good but after the first day everything started to fit well together and turned out into a nice game. Check it out!


What went right


It took a while (a whole morning) to decide the game I would do for this Ludum Dare. You are the Villain theme can be easily adapted to many videogame ideas just chaning good guys for bad guys, but I wanted something that suited the theme more naturally. I had two ideas in mind, one was doing some kind of Dungeon Keeper and the other was a game with a evil cat that wants to break alls the things in your house, well, like most of the cats use to do :). Usually I don’t like to use a physics systems without a good reason, I’m used to create simple verlet/euler integrators to have a decent physic/collision system and most games doesn’t require more than that. This way I have absolute control over the playability and fun factors of the game, one thing that I cannot assure when using a 3rd party engine. But from the beginning it was clear that I was going to require complex physics and collisions to make the game feel as realistic as it should.


I started creating the game boundaries and adding some static platforms with some boxes on top. For the cat I chose a round box2D collider, but the behaviour of the cat didn’t felt right when playing, the momentum and the low friction were affecting the playability too much and later on I decided to change the collision shape of the cat to another box. This circle collision code was later on used to develop the ball you see on the game. A lot of extra time was put on setting up the right values for the objects and the cat until the result was decent.


Wreck-It Cat

My two cats are adorable and they are too good to be cats, really. But all cats have a sixth sense to annoy you on the most inappropriate moments and I decided to base the main character on them (they look the same, no problem to choose one). The idea of showing what the cat was thinking came up very early, it was not difficult to imagine what the cat things when they break something, feel guilty is not in their dictionary. At the end it was one of the best ideas and people seem to enjoy them quite a lot.


One of the key features of the game is to break furniture and I hadn’t a clear idea on how to accomplish that. The tasks were two, first detect when an object must break and the other one split the object in different pieces.

The solution to detect when to break an object is not very academic but works. First I detect the collisions of the object and in case there is one the velocities of the object (both linear and angular) are used to calculate a value of damage to apply to the object. All physic objects inherit from a class named Element that takes care of these calculations in the cases the object is breakable. Each object has a robustness value that is decremented with each collision.

breaking bad

When an object is destroyed it is marked for destruction. Then, a routine generates particles based on the size of the object and transmits the physics values of the source object to the particles, adding a random factor. The particles are physic objects with a time to live and they use parts of the source bitmap as images. The graphic function that takes parts of the bitmap never worked very well, but I found myself spending too much time to code it and I chose to continue with the playability instead.

I had the breaking part done, which is quite entertaining by itself but how to turn this feature into a game didn’t come up until the second day. It was someway inspired in Katamari, you destroy small objects, you get stronger, you can destroy bigger objects, repeat until everything is destroyed. To make the cat gain weight was not an option so I went for the Cat Power skill, the more Cat Power the easier is to break things. The objective of the game changed from getting the most evilness possible to break everything in the house, a clearer objective very easy to understand.



I’m a programmer, doing graphics is probably one of my worst skills and I got surprised when I saw some comments of people praising the graphics quality. My target was only to have simple and understandable graphics. I didn’t want to spend many time doing art but I had no other option. Each new furniture needed a new graphic and I spent a lot of time doing art compared to my previous Ludum’s. Pixel art and a childish style allowed me to work fast, anyway anything more realistic is out of reach for my skills.


Level editing

How to edit the  level? how to put the furniture in the level? The first idea was going for the known solution, a tileset. But my objects had sizes and shapes so different that given the little time I had it felt like a bad idea, I would spend a lot of time setting up a tile editor for the game and then match what I have on the editor to what I see on the game. Then I aimed to do it via code, for one level it should be feasible. I have a function to put each furtinute of the game and I also have some macro functions to add the bookcases. This way I can add books easily with random size and color. I started populating the house from the bottom to the top, level by level with a trial and error approach. This way I could also hide the potential problems with the physic engine startup.


What went wrong


It had been a while since I used Box2D (2009), and I had forgotten everything so I started googling for some Box2D AS3 tutorials. As usual, the tutorials I found were from older versions of Box2D and the API had changed since them. I had to look the examples included on the Box2D package to learn something useful.

I had some objects with physics pretty fast, but then I had to program the cat, it is a different object because it’s controled by the played and you have to be very careful with with forces/impulses you apply to it because it’s very easy to lose the control of what’s happening with your main character. As expected using a physics engine was limiting the playability of the game. Changing the collider shape of the cat from a circle to a square definitely improved things, and I had to force some of the physics values of the cat object to deal with momentum. Probably not the best way to do it but what I could after a couple of hours of Box2D training.

Using Box2D in a two day project was a risk but I must say the engine is very good and it was worth using it.


The cursed lamplamp

Some people have had problems destroying the lamp on the top floor, I didn’t notice this while testing the game but definitely happens. The lower height of the top floor stops the lamps from rotating and it’s difficult to destroy it although possible to do with some patience or using the bed against the lamp.



Several people have complained the lack of sound in the game. To be sincere I could have done something but nothing of quality. It was almost 2 AM, very close to the deadline  and I was too tired to find a microphone and start recording samples with my cats . And about the music, well, the only programs I know to make songs are Amiga MOD trackers. I have a library to play them on Flash, but I’m  a poor musician, sure the game is much better without my music in there.



I had a great time developing this game and overcoming the different technical difficulties. It was awesp,e to do a game with cats too!  The challenge I have for the next Ludum Dare is to release something with sound, I have to check the competition rules properly, I think using standard MOD samples should be allowed if you compose the melody. Thanks to the Ludum Dare team and everybody participating in this wonderful contest. Happy New Year!

DNADream done!

Posted by (twitter: @kerrichal)
Sunday, August 26th, 2012 2:32 pm

Well, this is my entry, it’s about modifying the DNA of a plant to make it reach the sun. Again I couldn’t use all the compo time but I’m quite happy with the result anyway.




Gameplay test

Posted by (twitter: @kerrichal)
Saturday, April 21st, 2012 3:04 pm

Messi today had a bad day, but that doesn’t mean he isn’t the best football (soccer) player in the world.

I’ve always wanted to do circular jump’n’run game and this Ludum Dare edition theme is the best excuse to try it. The idea of the game is to collect the coins in the planet with the aid of a ball while you avoid some enemies. There is still a lot to do but there are some physics and items already present and it is nice to play for a while. The next steps is to add stage completion rules and some kind of time pressure.

First contact version is available to play. Controls are cursor keys and space to kick the ball.

Play Demo





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