This brilliant Sonic the Hedgehog version of the classic Super Smash Bros. games is really an alpha version because it actually has no major bugs or glitches and plays perfectly well, despite what the author says about it being a beta "test only" version - it works fine, the only issues are with a few unfinished menu options (and if you ever accidentally get stuck in one of those, press the F5 key to reset the game).
The game features 15 different characters for you to battle it out with (3 to begin with and 12 more that can be unlocked), including Sonic, Tails, Knuckles, Amy Rose, Cream, Shadow, Silver and 8 more!
See the Options in the game for the movement, attack, block and combo control key settings. There is a "Help / Strategy Guide" for the game which you can view in a pop-up window by clicking on the button below.
Your progress will be saved automatically so that you can unlock more characters and levels when you return to the game in the future, but you must play it in this website again in order to be able to re-use the saved data