Magigun

Delve into a wave based FPS with an eldritch horror flavour. You are constantly pursued by waves of lovecraftian monsters and the only thing protecting you from them is your arsenal of magic powered guns. Get new weapons and buy upgrades from the ever helpful merchant. Combine constant movement with precise aiming to avoid and kill enemies. Destroy them before the timer runs out. Survive as long as you can, though in the end, your will be consumed.