This add-on is a great version of The Super Mario Retro game. The only personal problem I have with this extension is that only part of the screen shows when clicked.

Its a button that opens a window to a website with the game

ok

good

bom a extensão e boa mas o mario nao pula e o som e ruim melhore! this extension is ok but this sound is bad and mario has no jump

After you know the controls, it seems to work pretty well. It opens a new window outside of firefox on which it runs the game. You can play/pause and quicksave the game, edit the sound, and controls.