This has to be one of the finest entries to TIGSource's awesome Bootleg Demakes competition. It's Gang Garrison II, a demake of the peerless Team Fortress 2. It's a two-dimensional version of the red-vs-blue class-based game we all know and love. In fact it's almost the same game... only flatter. It's got network code, heavies, snipers, scouts, the lot. There's a video of it in action after the link, but I think you should just download it and host a server - anyone can do it!