TubeJump is a pseudo-3D first-person platform jumping game for Linux) PC and for the GP2X handheld console. Instead of running, imagine driving a weird jumping vehicle.
While the GP2X version is limited to the resolution of its screen (although it has a TV out, too), the PC version is by default compiled to use a higher 640x480 resolution. (The GP2X does not have 3D acceleration so this is software renderer.)
The game has only four (4) levels included but with a image editor (the levels are just monochrome gifs) and a simple text editor you can easily create more. (If you do, please, send your levels to me so I can make them available here for others.) Each level can have its own texture to make them look more unique. See the included README file for more information.
This game was inspired by a simple game called Plain Jump (by Andreas Ess) for the TI-85 graphing calculator. It is itself probably a simpler clone of SkyRoads for MS-DOS.
TubeJump is released under the GNU General Public License, version 2.