The second game I ever 100%ed was Arceus and I still can’t stand the thought of picking it up again, years later. The first game was Horizon Zero Dawn, which is still fun.
I'm the kind of person who has no issues with moving on from a game with only 20% of the achievements/trophies unlocked after beating the final boss. If it's not fun, it's not fun.
I think the only two games I set out to 100% were probably Super Mario World, or Donkey Kong Country 2.
My recommendation for this will always be Cyberpunk 2077. There are SO many secrets and sub-plots to discover in the game, and every single one of them feels like an intricate, deliberate piece to the overall puzzle that makes up Night City.
To experience everything requires multiple playthroughs, which I normally dislike in long, narrative-driven games because I lack the attention span needed when it comes to repeating things in games. But CP2077 offers so many new ways to tackle every situation, and it's one of the few games I've played where it truly feels like a new experience on the second and all subsequent playthroughs. The writing and acting are spectacular, and going back and picking different options for various encounters will yield very different, yet authentic results.
I've 100%'d it and still went back and did at least 3 full playthroughs after. I can't sing this game's praises enough.
You can 100% the first three Spyro games in about 9-12 hours each. The first one can be done without any backtracking, even, since you have the same move set throughout.
I believe modern games take 100% runs way too far. I enjoyed 100%-ing the 3D Mario games... and then I got to Odyssey, and it was such a ridiculous slog that I couldn't get much further than the standard ending.
I just got 100% on Nier Automata, and I only loved it more as I played it more. Usually I hate any grinding in any game and will either skip any content that requires grinding, use mods to bypass it, or just put down the game and move on to another one. But the whole game just felt so damn good. I could just walk around for hours doing nothing because the movement felt so good.
There was quite a bit of grinding, but I didn't find any of it too bad. I got 100% in about 50 hours, which is my sweet spot. Any longer and I feel like the game is dragging on.
The last game I did 100% was Psychonauts 2. I loved the world and after playing the fantastic story it was a good reason to spend some extra hours revisiting the levels.
Cyberpunk 2077 with Phantom Liberty. 100+ hours of pure joy. And when you need to take the edge off, you can always spend a nice evening with the love of your life.
Oh that's really rare for me, since I'm not a person who can generally do "grindy" parts well if the grind extends past what is clearly the main intent of the game (that is, usually the story).
The last game I 100%ed is Pineapple On Pizza. A free 10 minute game, 20 if you go for all achievements. Says a lot about me I suppose. 😅
However, I do sometimes go after rare achievements because the ideas behind them sound intriguing to me. But I can't be arsed to go for all the other stuff, ingame and external, too. One good example of something I had to do is that the expansion Hate Plus has an achievement that for the longest time would get manually credited by the dev if, at a fitting moment in the story, you bake an actual cake and take a picture with it in front of the monitor at that scene.
Was time to bake something again, anyways. 🎂
At least personally, its a lot of the shorter, gameplay-focused games that always leave me wanting more, or wanting to further improve, without having some unbeatable new-game++++++++ mode or anything overly RNG based.
A couple games I've 100%ed that still have significant bonus/optional content outside the main plotline include:
Inscription - Willingly played through the story twice and spent nearly as many hours on the bonus new-game+ mode. Super solid gameplay, that while well explored in the base game, leaves plenty of room to further experiment and perfect your strategy.
Just Cause 3 - while there is a ton of bonus content, its not overly hidden, and the core gameplay is solid enough that challenges feel fun and rewarding, while travelling around gathering collectables is satisfying in a chill, podcast-listening, but not unengaging way.
Hotline Miami - after completing the game, I wanted to go back and get a A+ on every level because the gameplay was fun and I felt I still had more room to grow. "The puzzle" wasn't as fun, and I did use a guide, but I was just happy for any reason to play through the game again.
Wolfenstein the New Order - again, just a solid gameplay loop that made me want to keep playing, with bonus objectives that worked as an objective rather than a chore. Also, unlike later ID shooters, it doesn't have the "beat the whole game without dying" achievement, which just feels too punishing over mistakes that may be minor or downright unfair.
Cyberpunk personally, have done it a couple of times. I can just soak into the couch playing that game. My average playthrough time is about 150 amazing hours
If, by 100%, it includes 100% of the achievements/trophies, I can only remember Mary Skelter Nightmares¹, Odin Sphere Leifthrasir and Starbound as games I still enjoy after doing 100%.
¹og version; dunno if the updated version bundled with Mary Skelter 2 has trophies (didn't stop me from finishing it on the Switch, though e.e")
Elden ring. It's atmosphere and exploration just draw you in. Huge areas that are technically secrets. I haven't 100% it because of being locked out of certain questions but I'm sure I'm close. The gameplay is just so addicting to me I've got over 700 hours in it.
For Pokemon Legends Arceus I think what would prevent me from playing it again after 100% isn't the amount of repeated tasks to max out the Pokedex, most of which are fun and a few of which just suck. I think it's the slow dialogue/gameplay. When playing the actual game I'm usually having fun. When I'm stuck in a forced tutorial or dialogue it's just a slog.
I got all but one achievement in Subnautica, and all of the achievements in Below Zero (the sequel) in my first playthrough of both games, just from taking my time and thoroughly exploring both of the worlds and completing the story without even consciously trying to go for the achievements.
With that said, they are open world games and at times don't really give you a whole of guidance as to what you need to do next. So you are kind of left to explore and figure it out on your own. If you don't like that sort of game you might end up hating them by the end too.
The newer spider man games. I think it has a reasonable amount of collectibles and is fun to collect. The secret photo ops were tricky but not impossible if you've ever seen any of the movies. I've 100% every one including all trophies and new game+.
If you mean 100% achievements on Steam for example, I really enjoyed doing that with the following games:
Slipstream (2018): arcade racing game, 7.5h to 100%
SpongeBob: Battle for Bikini Bottom - Rehydrated (2020): platformer with some collectathon elements, 13h to 100%
Polyball (2017): think Super Monkey Ball, but a bit faster and stronger momentum iirc, gets quite difficult later on, and although the amount of content isn't ridiculous, it's very very hard to manage the requirements for 100%. My playtime is 59h, but I kept playing after 100% to get into the top 10 leaderboards on a bunch of levels, so I think it was more like 30-40h for 100%.
The Stanley Parable (2013): narrative game with some unconventional puzzle elements, 40h to 100%, but not really: one of the achievements is "play the game for the entirety of a Tuesday", so that adds over 24h. Another achievement is to not play the game at all for 5 years. Some people love this silly stuff, some hate it, up to you :)
Firewatch (2016): narrative game with exploration and some puzzles, 6h to 100%.
Armored Core 6 is pretty easy to 100% and it's really enjoyable the whole way there. Just don't bother with PvP.
And my favorite 100% grinding game that I keep playing just because I enjoy it so much, is the Earth Defense Force series. The game encourages you to play each mission with each of the 4 classes in each of the 5 difficulty levels. Even though clearing Hard also gives you Easy and Normal completion too, you're still looking at over 200 hours of gameplay, easily. The games have over 100 missions, tons of weapons to gradually improve, and at higher levels become true combat puzzles to solve with said weapons. Cheese is a way of life, in an enjoyable way.
I burned myself out of many a game as a kid attempting (and usually succeeding at) 100% them, so I learned my lesson. Nowadays I just play for fun and maybe go after the platinum if I liked the game enough. My time has value and I'm not going to squander it to "look at the minimap, go to waypoint/marked location, collect random collectible, rinse and repeat for 10-15 hours", nor am I spending dozens of hours grinding some random activity.
For example, I did almost 100% all Yakuza Kiwami. Did all side quests and enjoyed most of the random activities! Iirc those I had most trouble with were karaoke and billiards, but I still had tons of fun learning them and gradually getting better at them. But fuck me I'm NOT going to grind the coliseum for hours just to buy random weapons that I don't need but are arbitrarily required for the 100% completion.
I've also learned not to rush it. I frequently replay games that I like, so if I miss an achievement, that's fine. Maybe in five years I'll pick the game up again and grab the random achievement I missed the first time around. There's no need to sweat it, no need to read guides before/while playing the game and potentially spoiling me some major story events, and no need to immediately replay the game just to reach that random achievement.
That being said, the game I had the most fun with was CrossCode. Movement is fluid, combat is snappy, story and characters are fun and puzzles are actually challenging. It's the most charming experience I've ever had playing a game, and it's why it immediately jumped straight into my top favourite games ever. There is technically a "completionist list" within the game with some abdurd and missable requests, but it's not required to 100% the game and it's basically just a pile of challenges that you can tackle on if you feel like it. If you don't, you can just play the story, do the side quests and collect all the treasures, which is a lot of fun. The platinum only requires you to beat the story iirc, so you don't even need to do any of that; I did it because I liked the game and wanted to do it. Twice! I bought the game on PC and console and 100% it both times.
Most other games that I enjoy completing are platformers/collect-a-thons, such as Spyro, Crash (except Crash 1, never managed to finish it, but had tons of fun nevertheless), Ori, Celeste, PS1 Oddworld games, etc... and metroidvanias, if they are not overly long (basically every one I've played except for Hollow Knight).
The longest run I had was Final Fantasy XIII. I liked the game so much that I kept going back to it over the years, slowly chipping at the side content and grinding my way to max level. I got the platinum almost ten years after starting my save file, and I wouldn't have enjoyed it nearly as much if I attempted to rush it all in one sitting.
Only games I ever 100%ed were....Assassins Creed 1 and Rocket League, strictly by achievements only. Like I never made it past Champ in RL, and AC1 was really just beat game and collect flags. I never have the urge to 100% a game cause usually it's just a grind for grinds sake and that isn't fun to me
Sable was a perfect open world that I 100% in about 30 hrs. Totally didn't overstay it's welcome. I think they added a fishing quest after I played it so not sure how much that changed things.
Pokemon Uranium. The (in)famous(?) banned fan game that is still being developed. Minus a couple pokemon, it follows the Black and White philosophy of having no returning pokemon.
I've played through the game multiple times, beating the final fight for the main story and calling it there, without hating myself or the game.
Hell, I've even gone through the trouble of completing the pokedex once and struggled to find an early route bird for the last two entries I needed. Pokedex for that game can be hard because when it comes to 2 of the pokemon, you can only get one per save and must online trade to get the counterpart and 1 line is a trade evolution with no in game trades for it or trade evo items. Obviously starters require online trade, too.
Only problem I have with it is the fact I'm still waiting for the rest of the post game to be developed and released so I can hopefully get the unreleased legendaries you can find on the fandom wiki.
Baldur's Gate 1 & 2...the exploration of the wilds while so vulnerable in the first game is something I'll never get bored of while the second game just takes it to a whole other level with your power growing so immense. They still totally hold up with the extended editions!
Two games I have platinumed on PS4 that I still go back and play are Subnautica and Kerbal Space Program. Not sure if you mean 100% as in like scan and collect every item, or get all the trophies, cause I don't think I've ever 100% a game in that way.