Arguru has released, and updated to v2.0, a Mario Bros. demo for 2.6 firmware PSP’s using the Fanjita’s GTA Exploit Developers Package.

Some features:

Nice 24bit ripped sprites.
Skinnable sprites bmp.
256 random generated levels.
4 different enemies.
Flip/Kick enemy mario bros style.
V2.0 Changelog:

Added pause/resume game (press Start button in your PSP).
Enemies will flip back after 5 seconds.
Slighty improved graphics.
Improved tile "shadows".
Better map generator code.
"double scroll" in bottom sewer waters.
Program version and title on right screen.
Other minor changes.