So I made this list of medals I don't have, along with why I don't have them. If you know one or some of these medals are easier/less grindy than I think, and have advice, please do let me know in comments so I can attempt them.
Cheers.
Mechanical Commando 2:
Boss Run (50) - broken
Golden Commando (100) - will take too long
Punk-o-matic 2: Cover Band (50) - way too hard at that speed
zOMGies: Boom! (10) - broken
Santa Fu!: Santa Fu Master (50) - Oh, the GRIND!
Kill Kar 2: Kustomized (25) - broken
Dale & Peakot:
Big Winner (100), It's Impossible To... (100) - grind
Level Up!: Insomniac (50) - grind
MonsterTime: You Da Man (100) - Fucking Hard
T E T R I S ' D: Ninja (100) - damn hard
Miami Shark: Sailor (50) - grind
Medieval Rampage 2: All Achievements (100) - grind
Fig. 8: Professional (50) - broken
Dadgame:
Cheating Death (50), Dadgamer (100) - grind
Knightfall 2: Grandmaster Flash (100) - working on it, off and on
Epic Battle Fantasy 2:
Minigamer 1 (10), Minigamer 2 (10), Minigamer 3 (25) - grind
Bomb Diggity: Most (365) - I'm bad at this game
When Pigs Fly:
Halfway Home (50), All The Way Home (100) - I'm bad at this game
William and Sly: Sly Fox (100) - grind
Lastman:
Beetle Battle (100), Secret Medal (100) - Fucking hard
Epic War 3: All (460) - GRIND
Drop the Bomb:
Bomb Squad (10), Someone Set Us Up The Bomb (25) - broken?
D-Day Defender:
Get Out More (100), Master Tactician (100) - grind (I actually achieved Master Tactician, but the medal didn't come with the in-game achievement)
Seed of Destruction: I Am Illiterate (10) - broken
Medieval Rampage: 100 Achievements (100) - grind
Red Moon:
Orb Hunter (100), Red Moon Deity (100) - grind
Sonny 2: All (235) - grind
Doom Triple Pack: All (320) - grind
SeoMX Skating Video V2: All (10) - broken
Alkie Kong 2:
Full Case (50), Olympian (50), Survivalist (50), Drunken Deity (100) - grind
GAMES KNOCKED OFF THE LIST:
Tetraform
Tower of Greed
Invisible Runner (had a hunch I'd get this if I tried today)
M-Bot The Game
Extreme Gardening
Kill Kar 2 (non-broken medals)
Fig. 8 (non-broken medals)
Wee Express
Portal Defenders
Epic Battle Fantasy
Armed Prophet
Save The Goons
KingExodus
I'm only missing one :P
And that's M-Bot's go into K-9 mode thrice.