I found this old .blend, named horizontal 13, and i remembered my old demo game. Ball Roll '07!!!
basically you just move the green ball with w-a-s-d
w key jumps
a moves left
d moves right
just press ‘p’ and find suzanne
http://uploader.polorix.net//files/594/horizontal13.blend
just a clue, you may want adjust the level of zoomage,
another clue, you can jump whenever you touch a wall, that includes you bumping against the ceiling! use this to wall climb, its kinda fun 