I spent some time writing a simple 4k game using the standard kernel. I was getting the itch to write a program, it's been over a year now. It could use a bit of polish as there is no level or difficulty progression at the moment. Beyond that it is a complete and playable game. The screenshots don't show everything. I used both players missiles to create a scrolling starfield effect.
You're caught in an endless asteroid belt and it's your mission to ram and destroy the escaping cargo ship without crashing into an asteroid yourself. Your fighter ship is specially designed to take out the cargo ship by ramming it. You gain a point each time you destoy the ship. If you're destroyed, the game is over. There's only one life.
You fly on the outskirts of the asteroid belt, either just above or below it. Push up or down to enter the asteroid belt to try and take out the escaping Cargo ship. Your momentum requires an angled 45 degree attack, push up or down on the joystick to move to the other side of the asteroid belt. When on the outskirts, you can thrust forward or backward by pushing left or right. You can also turn on the afterburners by pushing down when you're on the bottom, and up when you're on top to fly faster. The game will continue as long as you can survive. Enjoy!
Comments and suggestions are welcomed. I may make some further changes and enhancements, although I'd likely have to bump up the rom size.