Here's a list of all the video games I've played to a fair degree, categorized by game system. Games I beat will have an asterisk in front of them. I will not list remake games, save for Pokemon LeafGreen due to it being a remake of the Japanese game Pokemon Green.
NES/Famicom
Super Mario Brothers 1-3
*Sweet Home/Suito Homu
*Final Fantasy 1-3 (beat 1 & 2 in a remake, played 3 on both an emulator and on the DS remake)
River City Ransom
*Shadowgate
Dragon Warrior/Quest 1-4
*Mega Man 1-6 (yep, beat 'em all)
MOTHER/Earthbound Zero
The Legend of Zelda
Zelda II
Dr. Mario
Kirby's Adventure
Super NES
*Super Mario World
Timon and Pumbaa's Jungle Fun (Unsure of name)
Paperboy 2
Monopoly
Star Fox
*Super Mario RPG: Legends of the Seven Stars
*Mighty Morphin' Power Rangers
*Mega Man 7
Earthbound
Kirby's Dreamland 3
Kirby Super Star
Tales of Phantasia
Dragon Quest 5
Arcade
*Teenage Mutant Ninja Turtles
Teenage Mutant Ninja Turtles: Turtles in Time
*Mortal Kombat 1-3 (beat the first one)
House of the Dead 2 & 3
Gauntlet II
Gauntlet Legends
*Gauntlet: Dark Legacy (beat it on the PS2)
Pac-Man and Mrs. Pacman
Galaga
Total Carnage
Sonic the Fighters
Soul Calibur 2
Playstation
Mortal Kombat Trilogy
*Digimon World 2 & 3 (beat 3 only)
*Final Fantasy 7 & 9 (beat 9 only)
Spyro, the original and Year of the Dragon
Mega Man 8
Monster Rancher 2
Monster Rancher Battle Card: Episode II
*Castlevania: Symphony of the Night
Sega Genesis, Mega Drive, and CD
Phantasy Star 1-3
Sonic the Hedgehog 1-3
Sonic Spinball
Sonic 3D Blast
Sonic and Knuckles/Sonic 3 and Knuckles
Vectorman
Altered Beast
Sonic CD
PC
Sonic R (The Tails Doll Curse thing is SCARY!)
Roller Coaster Tycoon
The Sims
N64
Super Mario 64
*Mario Party 1 & 2
Pokemon Stadium 1 & 2
Pokemon Snap
Legend of Zelda: Ocarina of Time
Super Smash Bros.
*Kirby 64: The Crystal Shards
Bomberman Hero & Bomberman: The Second Attack
GameBoy
Pokemon Blue, Silver, and Crystal
*Super Mario Land 1 & 2 (beat 2)
The Fidgetts (wins my award for worst game EVAR)
Snoopy's Magic Show
Ducktales
Monster Rancher Battle Card GB
Wario Blast: Featuring Bomberman (one of my first games ever)
*Kirby's Dreamland
GameBoy Advance
Pokemon Sapphire and LeafGreen
Mega Man Battle Network 3 (White) and 4 (BlueMoon, I think)
*Castlevania: Circle of the Moon and Aria of Sorrow (beat Aria)
Mario and Luigi: Superstar Saga
Kingdom Hearts: Chain of Memories
Nintendo DS
From The Abyss
*Feel The Magic: XX/XY
Pokemon Diamond & Platinum
Pokemon Mystery Dungeon: Explorers of Time
Etrian Odyssey 2
Digimon World Dawn & Dusk
*Castlevania: Dawn of Sorrow, Portrait of Ruin, and Order of Ecclesia (beat all three)
Bomberman
Phantasy Star 0
GameCube
Super Smash Bros. Melee
Super Mario Sunshine
Digimon World 4
Mortal Kombat: Deadly Alliance and Deception
*Tales of Symphonia (for those interested, I decided to keep Kratos in the endgame, not Zelos)
Playstation 2
Soul Calibur 3
Neopets: The Darkest Faerie
Mortal Kombat Armageddon
Final Fantasy 10, 10-2, and 12
Monster Rancher 3 and EVO
Kingdom Hearts
XBox
Fable
The Elder Scrolls 3: Morrowind
*Castlevania: Curse of Darkness (beat it with Hector only)
Star Wars: Knights of the Old Republic 2
XBox 360
*Fable 2
Gears of War 2
Soul Calibur 4
The Elder Scrolls 4: Oblivion
Nintendo Wii
Super Smash Bros. Brawl
Legend of Zelda: Twilight Princess