As far as I can tell, the game Duel Toys is now open source, apparently to celebrate the upcoming release of Duel Toys 2.
For those who don't know, Duel Toys is a 1on1 fighting game with characters from Capcom, RARE, Midway and SNK games (about 50, 23 of which can be played as), but with an RPG element. Basically, you can collect new characters to fight as and you fight against NPCs throughout the game.
More info here and here.
And apparently the sequel is an improvement. Here's some of the characters in the sequel:
Now... when can I see this ported to the Dreamcast, among other consoles? Not by anyone N/partik.
