Ludum Dare 34 — December 11th-14th, 2015 — Theme Tied: Two Button Controls, Growing

NOTE: Because of the Theme tie, we allowed everyone to pick either Theme. Using both was optional. To keep things simple, there will still only be one Theme category. Every category in Ludum Dare voting is an opinion, so you’re welcome to rate them as you see fit. But we encourage you to be fair in your scores to people that chose only one Theme, and not both.

ALSO: has an experimental game downloader over here. You may find it useful.

Back to Browse Entries


by siObyte - Compo Entry

-- PlantBoy --
The goal of the game is to harvest crops, but for your crops to grow you need water! And planet-rabbit-land, there is no water! So you must kill rabbits, harvest their blood, and use it to water your crops!

You will need either a Gameboy emulator, or a flash cart to play this, this is a *REAL* Gameboy DMG game!

-- Controls --
D-Pad - Move
A - Shoot
B - Water Crops

-- More details --
PlantBoy was a challenge, the goal was never to win, or even do well! I set out in the hopes of creating a simple, functioning *real* Gameboy game, written fully in z80 assembly in 48 hours.

Having about only a weeks experience in z80 assembly, and only little knowledge of assembly in general this was a big challenge. I'm happy with how far I got though, I plan to refine the code a little in the next few days.

Oh, and if anyone actually does play this on a physical Gameboy, and not an emulator, please record a video of it and show me! I've only been able to test this on emulators myself.

If you don't want to download an emulator, you can download the .gb file and play it on this website (It's a Gameboy emulator in flash!)

Downloads and Links




SketchyGalore says ...
Dec 14, 2015 @ 5:07am

Awesome achievement! I imagine programming in that format couldn't be easy! I had to emulate it of course, but it would have been neat to try it on an actual GB!

utoxin says ...
Dec 14, 2015 @ 5:13am

Sorry, can't run it (no emulator or GB), but it sounds really neat.

mrjorts says ...
Dec 14, 2015 @ 5:16am

Wow! Very cool to see a game boy game. It plays well, but it doesn't seem to get harder as it goes. I'm a little worried about why the plant needs to be watered with blood D:

danbolt says ...
Dec 14, 2015 @ 5:21am

I ran with OpenEmu on Mac OS X. If I had a DMG flashcart, I'd be on this in a second and changing the pallettes on my GBC.

How did you find assembly programming on the Game Boy? I've looked into C assemblers for it but I've never been so brave.

mackthehobbit says ...
Dec 14, 2015 @ 5:26am

Glad to see how this turned out! It's not really fun to play, but it's awesome that you got something functional writing just assembly. Great job!

xdigdoug says ...
Dec 14, 2015 @ 5:28am

This is a gameboy game. I was able to run this on a GBA emulator. Very interesting them, a little short though, only one level, but I don't know the details of programming for Game Boy.

Overall, a pretty decent game. For your next game, maybe make it so that you can collect more than 1 resource at a time (can only hold one blood)!

yumaikas says ...
Dec 14, 2015 @ 5:51am

This is definitely worth taking a little look, if only to see what it 48 hours of work on a GB game looks like.

Bemmu says ...
Dec 14, 2015 @ 6:04am

I'm really impressed you pulled off making anything playable on this platform in the allotted time.

Points for sound just because there are some! I liked the little gun bounce as you walk around.

As for the game, I wasn't exactly sure what to do. I guess collect blood, then grow that center thing and get crops. I got up to 6 crop before figuring out that probably nothing else would happen.

Bobrocket says ...
Dec 14, 2015 @ 6:46am

Awesome game! It would have been awesome to see how this plays on a real gameboy though.

prymidion says ...
Dec 14, 2015 @ 11:18am

Damn, it's pretty cool that you're capable of doing something like this in two days!

siObyte says ...
Dec 14, 2015 @ 3:38pm

Here's a video of it playing on a real Gameboy DMG, thanks to /u/gpremier on reddit.

refreshgames says ...
Dec 14, 2015 @ 4:37pm

Whoa! You did this in raw assembly! That is crazy awesome! I only delve as far down to GBDK and C. So, that must have been quite an effort! Once my replacement Flash Cart arrives I'll be putting this on there pretty sharpish!

Look forward to any further developments on this in the future. Damn, ASM jamming, that's nuts, crazy cool nuts :D

martincohen says ...
Dec 14, 2015 @ 4:49pm

Ran in on my GCW Zero. I had fun playing it. Amazing you did it in Z80. I bow to you, good sir.

George says ...
Dec 14, 2015 @ 6:29pm

Nice work on getting this working - I couldn't stand doing that much Assembly!

rogberth says ...
Dec 14, 2015 @ 6:32pm

Coding a game in z80 assembly for Game Boy. Now that is hard work! Congrats!

Dec 14, 2015 @ 6:41pm

Web version links to the download page, no web version there

siObyte says ...
Dec 14, 2015 @ 6:51pm


There is no "web" version as it's a Gameboy rom file, you either need to run it through a emulator, a real Gameboy (using a flash cart), or you can use the online-flash based Gameboy emulator I have linked at the bottom of the description if you don't want to download one yourself. (You still need to download the rom file, to use it on the flash-emulator page)

nonetheless says ...
Dec 14, 2015 @ 7:31pm

Really impressed, game is super pretty, great you did it with such constraints. Amazing entry!!!

tayl1r says ...
Dec 14, 2015 @ 8:19pm


mlepage says ...
Dec 15, 2015 @ 12:18am

Nice! I played it in the online emulator and it worked OK, I harvested 5 crops.

fluidvolt says ...
Dec 15, 2015 @ 12:27am

Holy smokes are you ambitious. Assembly! Week's experience! How?

Even though this is super simple, it's really astounding you completed a gameboy game in 2 days. I enjoy the simple graphics, they look really clean and sleek, especially considering the gameboy restrictions. Good job.

siObyte says ...
Dec 15, 2015 @ 12:49am

Thanks! It was definitely a big challenge, I tried to learn as much as I could the 5 days leading up to LD, and in the end I still had to learn things mid-LD. Like the rabbits, I had no clue how I was going to implement an arbitrary number of rabbits in assembly, but I got it figured out in the end!

The full source is up on github, though some things I could have done much better (I should really refine the collision code into a few nice sub-routines, that I can use for any collision), and github seem's to have bugged the indenting a bit, I should fix that to..

drludos says ...
Dec 15, 2015 @ 12:57am

A gameboy game in 48h? in assembly? Impressive! (it's the 2nd GB game I play during this LD, I guess GameBoy is the new cool, beware Unity! ;))

The game is also quite fun to play. Simple idea but effective, and I like the graphics! Well done!

NuvlearGames says ...
Dec 15, 2015 @ 9:30am

Very nice, took awhile to figure out the controls, but very good considering the constraints. Well done

josefnpat says ...
Dec 15, 2015 @ 5:33pm

Wow, this is one hell of an achievement! Really awesome job! This totally makes me want to make a z80 game now, wow!

lurils says ...
Dec 15, 2015 @ 8:18pm

simple but nice, congratulations on making it work perfectly.

Weloxux says ...
Dec 16, 2015 @ 11:01am

Really cool stuff! Loving the graphics, and most of all, the effort of doing it in asm. My score seems to disappear after 10 points, sadly.

siObyte says ...
Dec 16, 2015 @ 12:05pm

@Weloxux lol, yeah..I didn't get time to properly implement a numbering system with tiles, if you get a score above like, 255. Then the score tile will start going through the rest of the game tiles :p

local306 says ...
Dec 16, 2015 @ 4:39pm

Wow! That's super cool how this was built!

g12345 says ...
Dec 17, 2015 @ 12:22pm

Quite an achievement for doing a GB game in 2 days, in assembly! Well done!

OldPeculier says ...
Dec 18, 2015 @ 5:17am

Major ratings for the technical achievement. Yeah... not so great ratings for the gameplay. But Hey!—Z80 assembly! Wow!

randomhuman says ...
Dec 20, 2015 @ 3:33pm

Not much to the gameplay, but I definitely respect the ambition and graft required to put something together in assembly for retro hardware! And it looks good as well, with cute little animations.

scorched says ...
Dec 20, 2015 @ 7:26pm

You are the champion of making people click to play the game ( + emulator) :-) Looks fine, but I don't get how to press A and B in that emulator (I don't have a working gamepad)...

siObyte says ...
Dec 21, 2015 @ 6:23am

The controls on that web emulator appear to be the standard Z and X for A and B. :)

brainstorm says ...
Dec 22, 2015 @ 6:37pm

Woah, that's amazing. Porting a game to a Game Boy is really good! Though the gameplay itself it's quite simple and repetitive, what I really vote in this game is that you've a great achievement!


kmakai says ...
Dec 26, 2015 @ 7:40pm

Wow, this is awesome! Congrats on completing this and submitting to the compo, that really is an achievement. I'm looking forward to perusing the source, too. I really like the graphics, this would have been a nice look even if it weren't restricted to the Gameboy hardware!

My only suggestion/critique is that the counter for "blood" makes it seem like you could collect more than one at a time, which was slightly confusing at first, but overall not a big deal at all.

Really, awesome job. Congratulations on the accomplishment!

You must sign in to comment.

Mini Submission FAQ

TEAMS: Teams entering the Jam should pick a single representative to submit your game, or create a team specific account you can share. We currently do not support Team Voting, but sharing an account and together playing and rating games is acceptable.

CAN I ENTER BOTH EVENTS?: You should pick 1 event, whichever you think it’ll do better in. If the idea is strong, and everything plays well enough, you can go Compo. If you’re a perfectionist, and would prefer people to play a more polished game, do the Jam. Historically, more games are entered in the Compo, but with more people and more time, Jam games have the potential to be better (that doesn’t mean they are). Many solo participants do enter the Jam.

If you made 2 games, unfortunately, the website doesn’t support multiple submissions per user. To submit your 2nd game, you will have to make a 2nd account. Only do this if you made 2 games. Alternatively, if one game is better than the other, then consider just entering the better game.

CAN I KEEP WORKING UNTIL THE DEADLINE?: Yes! Immediately after the 48 or 72 hours, we do something called Submission Hour. As the name suggests, it’s an extra hour for you to package, upload, and submit your games. If there were catastrophic issues trying submitting your game, or you misunderstood how submissions work, that’s okay. It happens. We’re flexible. If you need advice, check with the folks on IRC. If you need an admin, get in touch.

CAN I KEEP WORKING ON MY GAME?: Oh definitely! You should! But for the sake of judging, keep the Compo or Jam version around. You can include a link to the Post-Compo/Post-Jam version of your game on your games page, but sure your main links are the original version.

PORTS: Ports to other platforms can be done after the deadline. That said, the sooner you finish your port, the sooner people can play your game, improving your chances of placing in the final results. For best results, provide a Web version of your game, or a Windows version with no dependencies. Also be sure to rate at least 20 games to improve your visibility (Coolness).

MY GAME CRASHES, IS UNBEATABLE, OR I MADE A TYPO: We allow you to fix crashes, win condition, or tiny bugs after the deadline. In a sense, this is like “porting” to support more players. We leave this open to interpretation, but generally speaking your game should be identical to the game you submitted. No new features, just fixing mistakes you should have caught had you been better rested.

MY GAME DOESN’T SHOW UP: If you can’t find your game, it’s usually because the URL to your downloads are missing ‘http://‘. Fix your URLs ( and you will show up. Alternatively, if you just posted it, wait a minute. The cache may not have refreshed yet.

NOT LOGGED IN?: If you get a message about not being logged in, even though you are, it’s because your web browser cached the non-logged in page. You can fix this by either refreshing your cache or clearing your cache. CTRL+F5 in many browsers. Chrome is a bit more work. Press F12 to enable Developer Mode, then you can right click on the refresh button and select “Empty Cache and Hard Reload”. This option is unavailable if you are not in Developer Mode.

[cache: storing page]