The first
Gothic has consistently been my favourite game for years now. It was an incredibly immersive action RPG for its time with fully voiced dialogues, daily NPC routines, music that provided great background ambience, and a world just fleshed-out enough that you felt like there was something bigger going on beyond the prison you are thrown in at the start of the game. It's just great all-around.
I also have a special connection with that game. I dipped my toes into modding it. I've sunk countless hours into discussing the game on the internet over the course of all these years since I first played it and met some interesting people who I would later talk to and drink with in person. So I might be biased.
And speaking of special...
World of Warcraft might be a close second on my favourites list. I know it's just a soul-sucking grindfest, but the people I've talked to, the rich lore of the Warcraft franchise, the intense, almost cartoonish atmosphere of some of the areas of the game... Actually, forget the people part. Azeroth and beyond was just too fun to explore. I would go sightseeing again anyday, if the entry ticket weren't so expensive.
I think I should also add
Super Hexagon to the list, just to throw off the people reading it. It's such a small, minimalistic, oddly psychedelic action game. You can move left and right and you have to dodge incoming obstacles. That's it. The game can be all cleared in under seven minutes (the game sets you a goal in lasting over a minute in each of the six difficulty modes and rewards you with achievements and a "game completed" ending cinematic if you manage it). It took me eighteen hours to complete.
Thes game is weirdly elegant in its simple design. It reminds me of Tetris - there is no violence, only some basic rules, and no real end goal, just a game over condition. Super Hexagon slightly increases in difficulty over time, then plateaus and becomes a test of focus and endurance as you try to beat your high score. I stopped seriously playing it two or three years ago, but I have these recurring cravings for more... SH is really lightweight and takes literal seconds to get up and running again. At the plateau,
the music slows down to a crawl, the colors tune out completely and before I know it, I find myself in a dark room, dodging white walls infinitely. It's like a flow/sensory deprivation simulator. You need to tune everything out in order to survive a long time. I feel like it left an insatiable, gaping void somewhere in my head I can never seem to fill. It's hard to explain. Everything disappears. And find yourself seeking to return to that state again and again.
As far as more recent games go, I finished
Spec Ops: The Line about a week ago, and it had an incredibly engaging story that I couldn't stop thinking about for a few days (as well as a really good soundtrack made up of tracks not originally designed to be featured in the game).