Developer Deniska (the brains behind the MapThis! app, and other PSP ports) has recently announced the release of a PSP-compatible build for the Nicky 2 game. This title was originally released to the Amiga/DOS platform by publisher Microids, and is a sequel to Nicky Boum, also released to the same platform.
The game is a platformer; players must navigate a series of maze-like stages as they uncover who's been removing the ladders and blocking off caves in Nicky Boum's homeland. Nicky 2's PSP port is based on a cross-platform engine developed by Gregory Montoir.
Those interested in downloading this game will want to remember a couple of important details: Nicky 2 is built to work with PSPs running on custom firmware 3.xx and above. It also doesn't support save-game or level codes, but it does support secret button codes that allow you to perform certain cheats (skip levels, get more bombs, etc).
Further details regarding this game such as controls and installation instructions are available in the file bundle readme. The developer also released a video of Nicky 2 running on the PSP, to give the readers an idea of how it looks.
Download: Nicky 2 for the PSP