Not bad at all if pretty basic for wave shooters, Even when pressing F11 text was cut off so if I missed some information in the main menu that explains something I had an issue this is why and I don't think upgrading was added because I killed the boss, went to the next level and nothing happened regarding upgrades. The game is fine the swarm of enemies helps stave off boredom but there should be a bit more variety then circle that chases you. And music, music should be in here.