I'm not much of an FPS player, but I am enjoying this game immensely. The weapons feel very good to use and blasting everything away is exceedingly cathartic. Playing on the higher difficulties feels challenging, but not in a cheap way, as you can play intelligently to always recover health if you need to. Before buying this game, I wasn't even aware there was a progression system until I started playing, but it has been implemented very well and it is very fun making your character more powerful.