Hmm, I'm thinking of such a game. I already made one, but by using a programming language. Who needs game programming languages when you can use GZDoom?
Instead of being unidirectional, you're inside a huge 32767x32767 sector (or how much is allowed) and can move in any of the four directions, shooting in the direction you're pointing. Going to the edges teleports you to the other side.
The gameplay is as follows: 50 enemies are spawned randomly. They look just like you and have the same arsenal, but less health and agility. All they do is follow you and start shooting when in range. Some of them will rather snipe you, by circle-strafing at a certain range, like wasps. What you have to do is hunt them down and destroy them.
Later on, the cruisers will come. They move slower, but are much more durable, and can spawn regular enemies. They also have a more powerful weaponry. Of course, you have to destroy them too. The game could continue ad infinitum, with more waves of regular enemies or cruisers coming, all until your ship gets destroyed. Health comes from destroyed enemies, who thrust spiky debris (damaging) and armor shards (healing).
Last but not least, the area is filled with deadly asteroids which move freely, and everything they collide on gets destroyed (except maybe cruisers, which are harder).