A game called Piercing Blow was added to steam greenlight a few months ago. it will soon be available as an official steam game. It's free-to-play and if it stays that way when it's added to steam I can't wait to play it.

Go check it out

It contains lvling, completing quests to get new guns, renting guns,getting new guns when you lvl up. Its a multiplayer/co-op game with deathmatch, teamdeathmatch, pistol only sniper only whatever and a cool feature which is called search and destroy much like the CS:GO gamemode except you can aim-down sights :) can't wait to play it and rekt all you ♥♥♥♥♥♥.