I have just finished my first game for the PSP. It's called Ozone and it's about a bouncing ball filled with air.
The mission is to find all the blue gems in each level and then proceed to the exit. The levels are full of items, enemies, traps, etc.
You can refill the ball with air pumps and green gems. You can also fire to the enemies if you collect yellow and red gems. If you run out of air, you die.
The controls are explained inside the game. Don’t forget using the brake button (square) to precise control the ball.