I reproduced part of the Catacomb Snatch game developed by Mojang in February, 2012 for a game jam in 60 hours.
To play the demo you have to use the arrow keys to move the character, press Z to run and X to shoot.
The code is separated into two files, canvas2d.js and game.js. The first one is a small framework that I have created to manage sprites, animations, effects and render, and second file has the game logic.
During the game, you can press the I and O key to see the debug log and debug collisions information respectively.