Insurgency is a great game if you want to get good at FPS. It takes some skill and strategy to win a match and it is overall a great game.

Unturned is a great game to play with friends especially when you download things from the steam workshop.

This is one of the best MMORPGs I have ever played. It combines the world of the elder scrolls with the online multiplayer experience of GTA 5.

This is a great game to play with friends that is challenging but can also be learned and enjoyed by a newbie.