This page is basically for keeping track of games I've beaten, and the rules I set for myself are:
Play blind
Hardest difficulty
No mods, glitching, cheats, or save states
Exceptions to these rules and/or further conditions are noted in the misc. section
Miscellaneous notes on completed games:
Pokemon games: EXP share turned off, didn't grind, only used new pokemon
Fire Emblem The Sacred Stones: [Erika's route: didn't use Seth or Myrrh, didn't grind, didn't use the warp staff], [Ephraim's Route: didn't use Seth or Myrrh, didn't grind]
Fire Emblem Path of Radiance: didn't use Titania or any laguz units
Call of Duty games: all non-DLC achievements unlocked, used a guide to find collectables
Donkey Kong 64: 101%
Super Mario 64: 120 stars
Ocarina of Time 3D: no Sheikah stones used
Skyrim: all non-DLC achievements unlocked (used guides to find some things), adept difficulty
3D Sonic the Hedgehog: didn't use any feature that wasn't available in the Genesis port
Final Fantasy Crystal Chronicles Ring of Fates: completed solo, didn't grind/farm
Fire Emblem Shadow Dragon: all gaiden chapters unlocked, didn't grind, barely used Jaegen and Caeda before "sacrificing them" early on to unlock the gaiden chapters, didn't use ballisticians or generals
Sonic CD: didn't use any feature that wasn't available in the Sega CD port
3D Sonic the Hedgehog 2: didn't use any feature that wasn't available in the Genesis port, played as Sonic solo
Metroid Zero Mission: 63%
Super Mario Bros. Deluxe: warpless, no life farming
Donkey Kong Country Returns 3D: didn't use super kong
Super Mario Bros. 2 (USA): warpless, set a save state at the beginning of each level, played as Toad and Luigi
Fire Emblem Echoes Shadows of Valentia: classic mode, did'nt grind, all dungeons cleared, no DLC
Super Mario Bros 3: warpless, no life farming
Super Mario World: warpless, no life farming
Donkey Kong Country: warpless, no life farming
Donkey Kong Country 2 Diddy's Kong Quest: warpless, no life farming, completed on normal mode
Donkey Kong Country 3 Dixie Kong's Double Trouble!: warpless, no life farming, hard mode "cheat codes" on
Yoshi's Island Super Mario Advance 3: warpless, no life farming
Super Mario 64 DS: 150 stars, all rabbits caught
Final Fantasy Crystal Chronicles Remastered: completed solo, all 3 iterations of each dungeon cleared, didn't grind/farm
Sonic 3 & Knuckles: played as Sonic solo
Crash Bandicoot (N. Sane Trilogy): 102%; all gems, including the one from Stormy Ascent, collected
Fire Emblem 7: [Eliwood Hard Mode: didn't grind, didn't use Marcus, didn't use secret shops], [Hector Hard Mode: didn't grind, didn't use Marcus, all side chapters unlocked except for A Glimpse In Time, didn't use secret shops, recruited Geitz]
Crash Bandicoot 2 Cortex Strikes Back (N. Sane Trilogy): 100%; all gems collected
Metroid Samus Returns: hard mode, 100%
Super Metroid: 59%
Metroid Fusion: 47%
Fire Emblem Radiant Dawn: didn't have path of radiance save file transfer bonuses, almost all full turn bonus exp requirements met, didn't bring any laguz royals to the tower
Metroid Dread: 36%
Banjo-Kazooie: all jiggies, musical notes, and honeycomb pieces collected
Fire Emblem Awakening: lunatic, classic, didn't grind, didn't use any of the "Wireless" features, no DLC, paralogues 1-4 and 12 all completed as soon as they became available
Castlevania Symphony of the Night: didn't grind, true ending, looked up how to progress at 2 points and how to beat an optional boss
Spyro the Dragon (Reignited Trilogy): 120%
Castlevania Circle of the Moon: didn't grind
Crash Bandicoot Warped (N. Sane Trilogy): 63%; all gems (including those from Future Tense), other than the ones that require relics, collected
Castlevania Harmony of Dissonance: true ending, didn't grind
Sonic Adventure DX Director's Cut: all stories, other than Big's, cleared
Spyro 2 Ripto's Rage! (Reignited Trilogy): 100%
Spyro Year of the Dragon (Reignited Trilogy): 117%
Banjo-Tooie: everything collected except for 1 jiggy and 1 cheato page
Sonic Adventure 2: hero and dark stories completed
Super Mario Sunshine (3D All-Stars): every stage cleared except for the 100-coin shines