I got this game very cheap off of Steam and am pleasantly surprised. It's a very solid top down shooter with minor rpg elements that will last upwards of ten hours depending on how you play.
The action is frantic, the difficulty is there however it never feels too hard, the monsters are varied and on the whole I really enjoy it.
It's probably not the best shooter on the market of it's kind, however it's more than worth the small price tag. Recommended.