Move with WASD keys or arrow keys. Hold down mouse button to fire (you fire toward mouse pointer).

Pick up tiles to power up your Contention Cannon. The Contention Cannon is powered by the contention between mutual enemies. Picking up two tiles in sequence who are natural enemies (e.g., donkey and elephant, because democrats and republicans are natural enemies) makes them combo together into a group in your tile queue. A bigger group means more firepower.

You can chain together enemies for very big groups, as long as each tile in the group is a natural enemy of the tiles on either side of it (e.g., cat-dog-cat-mouse-elephant-donkey, etc.).

Tiles are added to the right end of the queue, and you always expend firepower from the rightmost group in the queue. Starting a new group on the right means you start firing from that group right away, but you can add tiles to a group as you're expending it.

If there are lots of tiles on the screen (in your queue and on the field), new tiles appear less frequently, so you can't just wait around for that next perfect tile you're waiting for. You have to use up the tiles on the screen to make more appear.