I enjoy keeping track, mainly for my own records.

Game Boy

Final Fantasy 5 Advance

MegaMan 2

Disney's Magical Quest 3 starring Mickey and Donald

Genesis

Taz in Escape from Mars

N64

Disney's Tarzan

Perfect Dark - Secret Agent

Pokemon Puzzle League

Snowboard Kids

Star Wars: Shadows of the Empire

Blast Corps

Snowboard Kids 2

Chamelon Twist

NES

Dragon Warrior

Ninja Gaiden II: The Dark Sword of Chaos

Ninja Gaiden III: The Ancient Ship of Doom

PC

Barkley, Shut Up and Jam: Gaiden

Half-Life

Portal

PS1

Skullmonkeys

Syphon Filter

Castlevania: Symphony of the Night (both castles)

PS2

Kingdom Hearts II

Maximo vs. Army of Zin

God Hand

SNES

Phalanx

Sonic Blast Man

SoulBlazer

Super CastlevaniaIV

Wild Guns

Xbox

Metal Arms: Glitch in the System

NBA Ballers

Panzer Dragoon Orta

Unreal Championship 2: The Liandri Conflict

Blitz: The League

King Kong: The Offical Game of the Movie

Xbox 360

All Pro Football 2K8

PS3

Metal Gear Solid 4

For what it's worth, Barkley, Shut Up and Jam: Gaiden was the most entertaining game I beat this year.