C-Dogs

Classic overhead run-and-gun, supporting 2 player co-op or deathmatch. Customize your player, choose from many weapons, and blast, slide and slash your way through 5 unique campaigns. There is also a campaign editor and hundreds of user-submitted custom campaigns to try. C-Dogs was released in 1997 as a freeware DOS game. It was later released as open source and the source port, C-Dogs SDL, boasts many improvements like 4 player local multiplayer, LAN multiplayer, and more campaigns.