I've been playing Deep Rock Galactic a lot recently. This is seriously one of the best things I've played; everything about the game is awesome and it's great to play with friends, or just do multiplayer with strangers.
You're a dwarf, one of four classes (Scout, Driller, Gunner & Engineer) and you play cooperatively with three other people to solve missions in random-generated caves. Missions vary from collecting stuff, to laying down pipe-lines to salvaging lost equipment and while doing this, you're constantly being attacking by the wildlife. I mean, I can explain more, but there's tons to explore and enjoy; honestly my favourite shooter game at the moment. Just look it up on Stea for example to see for yourself.
Also, because of the Steam Sale I bought myself Dirt Rally 2.0; haven't played racing games in ages, but used to love that when I was younger. I had this (very old) Xbox game called RalliSport Challenge that was quite challenging indeed for 10-12 year-old me. Wanted to have a go at something similar again. 100GB of download later, I did my first races a few days ago. Difficult game, but it was fun!!