The funny thing is, the one theme I actually did plan out in my head was “Advancing Wall Of Doom”. So here’s my design (Kabe Shoujo).
It’s a vertical shmup where you’re a magician. You’ve got the usual 3 kinds of shots: red shotgun spread (shot button 1), blue laser (shot button 2) and purple homing bolts (hold both shot buttons down – makes you move slower).
In addition, you can summon a “wall” of 6 or so magic circles (the Advancing Wall Of Doom) which forms a line about 1/3 way up the screen. You start with the wall active.Each circle starts as a random colour – red, blue or purple.
Enemies who touch the wall are destroyed. Every time an enemy touches the wall, it moves back a bit.
Now there are 3 kinds of enemy bullets – you guessed it: red, blue and purple. The wall circles only absorb bullets of the same colour. However, if you fly into the circle and use one of the shots, the circle will change colour after a short duration. The trick is to change the circle colours to best absorb the massive barrage of oncoming fire.
Also, you can dispel the wall by using the Bomb button – doing so makes you briefly invincible and unleashes a super attack. You can re-summon the wall using the same button, but you only get 3 re-summons per life.
I’m planning to have 1 tutorial stage (really a mini-stage) and 1 real stage.