Collect twenty stars - get a big cake!!
This is Punk (Birthday Card version), it is based on an old Amiga game myself and a friend nearly made back in the olden days using AMOS. It plays like a bonus screen in Rainbow Islands or something. Or course, it not quite the same because you have to use the keyboard to control it rather than a digital joystick, which never seemed to catch on for the PC.
a - left
d - right
w - jump (hold for bigger jump).