Lylatitude has emailed us his homebrew game for the PSP, In The Air, Build 2060112. In The Air is a re-written plane shooting game, originally on Windows. You need to rotate your PSP 90 degrees to play. The source code is released too. Message from the author:

In The Air (ITA). It is a shooting game. And on PSP, the screen is rotated 90degree. The original game is based on WinAPI on Windows platform, from wzysj[at]citiz[dot]net. And I rewrite the game to suit to PSP platform, make it working and add some sounds. I know the game is not a big one and it is written without GU(in sdk). Just writing VRAM buffer simply. The source is written in C style.

The game works OK on firmware 1.5, but I must say that there are 2 bugs: sound control and exit exception. These 2 bugs wouldn't influence PSP after exiting the game. I have tested it on my PSP for many times. The problem may be caused by the "huge switch" and playing sound.