Beating Cuphead and CrossCode, two notoriously difficult games.
I would also count Super Smash Bros. Melee (100%) and Pokemon Yellow (all 151 Pokemon on level 100 with maxed out stats).
Building a Railway that goes out 1000 blocks in Minecraft Survival Mode.
It probably doesn't mean a whole lot now the game's been out for three years, but I finally got all 900 Koroks in Breath of the Wild.
Recently this morning on the (Nintendo) mobile gacha game, Dragalia Lost, I got the 5 star adventurer, Gala Leif, on my 3rd single summon! And the odds of obtaining him was a low 0.5%!
I beat the first level of Plutonia with the Brutal Doom mod enabled...
...on the "I'm too young to die" difficulty.
Recently, I was playing Super Mario All-Stars on my Nintendo Switch, and I managed to get the secret White Toad House unlocked in Super Mario Bros. 3's World 1 on my first attempt on it!
Recently this morning, I finished Chapters 1 thru 14 of the (Nintendo) gacha game, Dragalia Lost, 100% complete on Very Hard difficulty
- I remember many years ago when I completed Lego Star Wars: The Complete Saga, and Lego Star Wars 3: The Clone Wars 100%.
- Completing Green Hill Zone Act 1 from Sonic the Hedgehog 1 under 31 seconds!
- And defeating Grim Matchstick from Cuphead without taking ANY damage TWICE!
(Yeah, it's a long story why I did it twice...)
I've beaten Emerald and Ruby Weapons in Final Fantasy VII without Knights of the Round.
Recently, I beat Sonic the Hedgehog 1 (Via the awesome SEGA Genesis Mini) in one session* without using debug mode, and with 4 out of the 6 emeralds collected!
*I was trying to attempt a 1cc run, but I was force to use a continue in the final zone against Pingas Guy.
Yesterday, I completed the entire story mode of Pokémon Sword Version WITHOUT using Dynamaxing nor Gigantamaxing on my Pokémon the whole time.
My secret: I use my transferred Pokémon from my 3DS to Sword via Pokémon Home in my game.
I've beated Guitar Hero 1 & 2 expert on ps2 with a dualshock. (I HATE MISIRLOU, IT'S THE WOSRT SONG POSSIBLE TO PLAY WITH A DUALSHOCK!!!)
I collected all 100 Cat Shines in Super Mario 3D World + Bowser's Fury. B)
Just this morning, I beaten Paper Mario in a No Hammer, No Toad House, No Life Shroom run at level 20 (HP: 35, FP: 30, BP: 30), with the added bonus of not dying once in the entire challenge playthrough. Time to update my Signature
I 100% completed Mortal Kombat Deadly Alliance for GBA in a single night.