What a lousy game! Cannot be completed on Firefox either -- the level with the huge pit and intended infinite jumps is impossible on Firefox and only can be done on Chrome, as you only get like 2 or sometimes 3 jumps rather than infinite on Firefox there.
Ripped music from Super Mario Bros. as has already been stated by others.
The "ducking" is really bad as you effectively have to be running then press down for it to "count" and it's not really ducking as getting through some of the low overhang parts.
The "graphics" are just stickman so, not much to say there.