The Witness is not a game to take lightly. When you first see the color palette, the island setting, and the overall look of the game you may be lulled into a false sense of security and ease, but it will soon chew you up and spit you out.
Dragon's Dogma Dark Arisen on PC is just as solid of a game as it was on Xbox 360 and PS3. Maybe now even more solid given the bump in resolution and framerate.
If you are worried about bugs in Fallout 4 you may want to wait a month or two for some patches, but the game is playable, and mostly fine now.
Call of Duty Black Ops 3's story is much more of a future tech adventure, following in the footsteps (tech-wise) of Advanced Warfare. You have more parkour abilities, jetpacks, boosts, and more.
Halo 5 is a fantastic game, one which could get better with time. Tweaking systems like Req cards, adding maps via DLC (all of which will be free) and Forge, and honing the playlists in arena will ensure the game gets better and better.
Anno 2205 can be as easy or hard as you want, and everyone should have a great time playing it.
Destiny The Taken King, and subsequently the 2.0 update for the game, change the basic fundamentals of how much of Destiny works.
Trials Fusion Awesome Level Max DLC is well worth the $9.99 Ubisoft is charging if you really enjoy the base game and want some crazy-fun levels and more goodies.
Devil May Cry 4 Special Edition is a solid package for people who loved the 2008 release exactly as it was, but wanted a bit sharper image and higher framerate.
If you've been waiting for a game that gives you the actual feel of being a professional driver, I haven't found another game that does it as well as Project CARS.