Couch Multiplayer Co-op and PvP

Now it's possible to play with 4 players in 2 modes. Siege: the old one with a new name. Hordes of enemies will attack you and the other players. PvP: the only enemies are your opponents (the other players). After selecting a mode, a menu will open to let the players join and, if they want, change the keybindings, before the game starts.

At the moment the only available players colors are blue, red, purple and yellow (any resemblance to colors of people/turtles is purely coincidental) and they are based on the order in which the players join. More colors and a better way to select them will come soon.

Characters now change expression when hit, so you can feel better their pain. There are changes in the textures too. They should now look much cooler.