I created this game with a team at the Exile game jam for a one night jam with the theme "no buttons". We cheated a bit and ended up making a game with lots of buttons.
The player is inside a giant robot and has to defend the city from an alien invasion, but they don't know how it's controlled. The possible controls are at the bottom of the screen and their functions are randomised at the beginning of the game. Pressing the buttons could cause the robot to shoot, transform, walk, turn pink among other things. Try to survive the invasion for as long as possible.