This is a very mild violation, but I like to play these puzzles: https://www.chiark.greenend.org.uk/~sgtatham/puzzles/
...except that I create a custom difficulty level which is quite a step below the easiest difficulty and then I almost rather speedrun the puzzles.

The Rectangles puzzle at 5x5 size has been my crack for the past months and I'm at about 13 seconds now (using my phone as input).

I mean, it's very casual speedrunning. No one cares about my time, so I actually never timed myself before just now. But yeah, I just like the different challenge of thinking fast rather than complex.

I often use cheats to remove grindy and boring bits beyond a certain point. Usually the difficulty curve is pretty bad and a game is only hard or challenging in the beginning. So I play as intended until I reach a point at which it's just a matter of time and not skill. So I just give myself a ton of crafting mats or currency or whatever so I can focus on the fun and interesting parts of the game.

I played stealth games like Hitman like a mass murderer.

I also play the "infiltrator" class in Mass Effect without tactical cloak. I mean it's a mix of soldier and engineer, why should it be focused on stealth ?

Turned off the aggro on the patrolling demons in Murdered: Soul Suspect, because an otherwise peaceful detective adventure - where you play as a ghost investigating your own murder - really didn't need the random stressful action sequences 🤷‍♂️ (Sadly you can't turn off the floor traps, but at least those are stationary.)

I collect all the stars since GTA III.

I also play everything on Easy because I have a life.

I actually don't know the way you're supposed to beat Super Metroid "correctly." I've always done what I ended up learning was a major sequence break resulting from a bunch of bomb jumps to get the power bomb early, and use that to get some other stuff that allows me to beat the game out of order.

I also never start Metroid Prime without immediately getting the double jump. I used to be up there on speed running that game. I don't play the player's choice or switch versions whenever I decide to crack it out. The original was literal perfection.

Mindustry It goes from a tower defense game to a logistics game for me Forget enemies, How can I haul the most amount of shit down data pipelines without letting a single container hold items for too long? My worlds are just a absolute mess of conveyor belts going everywhere, transport drones coming and going, items being produced, used, machined and consumed everywhere And the only purpose is to give me more endpoints to grow it

About half the time I play Cyberpunk 2077 as a first-person RPG. The other half of the time I just play it as a city/driving-simulator.

If I can get it working, I will absolutely use debug mode on pokemon fan games because it saves me time not to have to do things like going back for healing my party, grinding to a certain level defeating bosses I'm not supposed to using cheated in legendaries, etcetera.

Definitely not developer intended, nor am I sure this would count for an intended answer to the question. Otherwise, I cannot think of any other answers to this question.

Watch Dogs 2. I’ve barely touched the story and just mess around.

I'm starting a run of Project Zomboid without zombies

battlefield 2042... unless i have a squad or some friends, i rarely play the objective. i mess around with gadgets, try to fly the wingsuit to weird places, try to launch vehicles where they don't belong, try to find clever ways to kill people, whatever. my score is always trash and my team hates me but i'm usually having a great time.

Splatoon

Play dualies, focus purely on anniahlating children with complete disregard for the objective.

I don’t think I’ve ever actually played a story mission in Just Cause 4

I guess risk of rain 2.

I've fought the boss before but never any of the new ones. I don't touch lunar items I just get to the last teleporter and loop around again and again. I rarely end the game I just play until I get bored and then close the game.

Still got like 400 something hours in the game on steam and on PS4 that I don't even know

This is pretty much the basis for the entire speed-running community. Maybe not totally different (like walking around as a peaceful tourist in Hitman), but definitely not utilizing mechanics as intended

I used to just cruise around in The Crew, enjoying a chill ride around

Almost all of them. Including the game of life.