The Proton Orders
A downloadable game
In The Proton Orders, players create robots called Frames and shoot their way through 49 levels of atom-collecting action where they accomplish tasks like defeating enemies or escorting convoys around the maps. By doing so, they collect resources that can be used to improve their frame and its weapon. There are multiple types of frames and weapons to unlock and the player gets active and passive abilities as well to unlock.
The opposition comes from ten enemy models, part of four faction of enemies, each with their special abilities and attack methods that the players have to deal with. This game can be played in four players split-screen co-op and also supports controllers.
Please note that it's also horribly unbalanced and might still contain bugs!
Just unzip everything at the same location and go!