A simple beat em up used at a game workshop that I recently conducted.
level-1 : Streets of Rage (stage 1)
boss-1 : Batman (SEGA Genesis version)
level-2 : Streets of Rage (stage 5) (remix)
boss-2 : Thunder Force IV boss
All sprites from http://wwwdynapaul.wikia.com/wiki/King_of_Fighters_Sprites
Sound effects mostly from http://soundbible.com/tags-scream.html
<- walk left
-> walk right
a Punch
s Kick
Several but this was supposed to be educational. Fixing them is left as an exercise to the reader.