Frankly, with me, I’m surprised I finish any game and I’m sure most y’all wonder too, but for me, I’m really surprised I finished and loved all the BioShock games. There was so much going on and it wasn’t easy. It was tough as balls, especially first two. So I’m always amazed I finished those.

Celeste. Though I never did complete the Farewell expansion.
I'm not sure I can deal with 10,000+ more retries.

Volgarr, but I didn't get the 'good' ending.

Peggle 2. Every achievement.

Volgarr? ​​​​​​
I deleted that game in like five minutes. I'm pretty sure that is the "Good" ending

You should re-install it. Maybe you'll finally appreciate its brilliance*.

*terribleness.

BTW: Fuck that game.

Most recently it would be The Last of Us. The game has so many damn tropes that I fucking despise (forced stealth, breakable weapons, characters that walk/trot at a snail's pace, limited ammo) but the characters and story carried me through.

Star Wars: Jedi: Fallen Order - this game had so many flaws and if it didn't carry the Star Wars name it would have been panned and forgotten inside of a month. I certainly felt like quitting after traipsing my way back through level after level using a broken ass map. Not sure why I trudged through, maybe because of the hype of some big reveal at the end that equated to nothing more than a wet fart of a cameo. I'm a big Star Wars nerd, but the fanbase as a whole just overdoes it sometimes. This is one of them.

I don’t know that I’d say I was surprised, exactly, but I whatever-the-gaming-equivalent-of-hatefucking-is Arkham City. Arkham Asylum was one of my favorite games I’d played in ages, and I was colossally disappointed that the really tightly designed areas that encouraged so much exploration were replaced by a pointlessly large, bland open world. I was miserable the entire time, but I’d spent my $60, I’d taken time off work in anticipation, and I wasn’t going to let myself be defeated. So instead, I spent 15 hours or whatever playing through a game I actively disliked.

I’m surprised I played through Avengers enough to platinum it.

Others that spring to mind are games that I stopped playing for a while and picked back up years later to finish:

Beyond Good and Evil - this was fixed in the HD port, but originally, if you died during the final boss, you had to replay the space battle preceding it all over again, and the process was so time-consuming to get back for the final confrontation that after a bunch of attempts, I was just “eh, close enough”. But it was a breeze on the HD version, which did add a checkpoint after the aerial assault.

Rayman Origins - again, the last level. Just one of those things I had to play over and over and over and let rote memorization and muscle memory sink in.

Donkey Kong Country: Tropical Freeze - the funny thing is by the time I picked this back up, I couldn’t remember where I’d gotten stuck. I got through whatever level was once tripping me up on my first try or something like that, and nothing really gave me a hard time through to the very end.

I'm surprised I not only completed Arkham Asylum but also got 100% on all the achievements. Oddly enough, even though I have the limited edition sitting in my closet I never opened Akham City. So one of my biggest gaming accomplishments along with one of my biggest regrets. But maybe I wouldn't have liked it either.

The Witness

I'm only surprised because there were so many hidden puzzles, and because of The Challenge, mini-game. Argh, that one was tough and incredibly frustrating, but it was so rewarding to finally complete it. It was a great game!

I would also say Arkham Asylum. Took 2 chances, but wound up loving and finishing and got like 80%, but wouldn’t do those challenges for 100%. I was satisfied. But so glad I gave another chance.

The Souls franchise. I'm usually terrible at games that are perceived as difficult, but after getting hang of the series it really wasn't so bad outside of Orphan of Kos.

I played through 5 of the titles this year, in a row. I've never done anything like that before.

The Last of Us- not my type of game. Didn’t find the gameplay interesting at all. Took a couple months to finish but kept coming back about once a week because the storytelling and acting is the best I’ve ever seen in a video game.

Been meaning to pick up Demon’s Soul. Was told this is the first one so figure I should start there. Not sure what to expect except it’s a medieval type sword based action game. Guessing a bit there. But I’ve heard about it for so many years constantly I can’t ignore it much longer.

^ For me, Demon Souls is the easiest one to get into, the first Dark Souls is the hardest (due to being rather dated early on).

Cool, I’ll start with that and then move onto the rest. I’m a sucker for highly difficult games. If I like it then I play the hell out of it and may get good at it. I always hear about how hard the Fire emblem games are but I found the difficulty very satisfying, until the 3ds games where playing on very hard really meant it. Always found starting the game over and trying to do better a joy. I grew up on games like Kid Icarus, Contra and Phantasy Star 2. Hard as hell but kept playing them until I had them mastered.

Witcher 3. I'm not huge into action RPGs (or RPGs in general), especially now that I don't have the time to dedicate hours and hours to gaming. This one though came around just at the right time. I was still in the Navy and underway when a guy departing the ship sold me his PS4 with like 10 games for a ridiculous price. One of the games happened to be Witcher 3 and I got bored one day and decided to pop it in. I failed my first mission and almost quit but decided to stick it out. Fantastic game. Loved it so much that last year when I got recalled to active duty I bought it for the Switch to replay it and the DLC (something I have never done before). Heart of Stone might have been one of the best stories in any game I've ever played, blew me away the effor they put into it and it really sold me on looking at DLC for other games. All said I put around 80 hours into my first playthrough and 115 into my second. I'm already wanting to play it again.

Arkham City Knight was such a disappointment. I also hate-played it up until it required doing something with the batmobile that I tried over and over again. Finally I realized I hadn't been enjoying the game for several hours, and just dumped it. I watched a video for the ending, and found something more fun to play.

For me, it was Clicker Heroes on the PS4. I originally tried it out and thought it was the dumbest thing ever. When I went back to it several months later, I noticed that the game was still "playing" while off. It intrigued me enough to try it out again, but I still found it pretty dumb. Unfortunately, it was one of the first PS4 games I played, and the internal calculations were kind of interesting, so I finished it out enough to 100% the game. Admittedly, the vast majority of that game wasn't done with any manual intervention on my part.

Wow, I really loved Arhkam City and thought it was the perfect sequel, opening up the previous game and expanding on its story.

Now Arkham Knight on the other hand, I'm pretty sure I deleted it after rage-quitting, following the fortieth time I drove my Batmobile off a cliff during a forced.

I'm horrible at eye/hand coordination, so I'm happy with ANY game I actually finish. Probably why I loved the Uncharted series - challenging enough not to bore me, but not so hard that I get frustrated and quit. I've finished all those.

Just finished Super Castlevania IV. Didnt seem as challenging as NES games which I never expected to finish (1 and 3, cant be bothered with Simon's Quest).

Whoops. I meant Arkham Knight was the one I hated. Arkham City was fun, although not as fun as Arkham Asylum.

I loved Arkham Asylum as it was one of the first games that I platinum and to be able to execute the fighting combos was an accomplishment in itself. I agree with Adam that Arkham City left me disappointed and Arkham Knight was even worse.

Rayman Origins is so visually pleasing but so freaking frustrating to play since I don't have the hand and eye coordination to master the game.