All I got done is a one-screen prototype. The final thing would involve a multi-screen base that you disable, then enter inside.

There are three shot sizes. When shots of the same size collide they create a bigger shot.

Based on an idea I had while doing something unrelated earlier today.

Arrow keys to move, Z to shoot.

I wanted to make it so my head would only appear on screen while commenting on your performance, and then have a secret boss fight if you shoot me enough, but I'm already 40 minutes over the limit and I haven't even started on that stuff yet. The floating head tracks more stats than you might think, although it only ever comments on your ratio of enemy kills. It compares how well you've done during your current life to how well you've done in the rest of the game so far, basically.

This is a Kururin-like.

Use arrow keys to move the Earth and its dear Moon through the space fortress without crashing.

Hold shift to move faster.

I was going to make some kind of asteroids game. I tested it before I had the screen clearing every frame, and ended up making a game around the drawing with game objects.

Fight the evil Space Head (you can't win)
Destroy the missiles before they hit you.
Or you will die.

Loosely based on NS-Shaft.

A star is engulfing a stream of matter. Don't fall out of sight, and don't get swallowed.

Arrows to move.
You get more points the farther you are from the star.

Loosely based on an idea in the fourth paragraph of this.

Arrows to move. Z, Space or Up to jump.
There is a secret ending.

Fight Earth for the glory of camels! Lock on with your deadly laser and it'll destroy everything in its path! Kill as many humans as you can!

A Galaga-like action game. Shoot down the Insector waves with three different weapons!

EDIT Oct 2011: Reduced enemies from 27 to 20.

Try to reach the STAR by using your magical SPACE JUMP! But mind your JUMP POWER - you wouldn't want to collide with any SPACE SPIKES!

I have a bad feeling this idea may have been done before