Here is the full list of all 25 Megamind: Ultimate Showdown achievements worth 1,000 gamerscore.
Defeat Psycho Delic without dying as Megamind
Complete the Game as Megamind
Complete "Blue Tighten Battle" Level as Megamind
Defeat Blue Tighten without dying as Megamind
Complete "The Parklands" Level as Megamind
Defeat Hot Flash without dying as Megamind
Unlock the Sticky Boots mini-game as Megamind
Complete "The Overpass" Level as Megamind
Unlock the Mega-Blast mini-game as Megamind
Complete "Uptown" Level as Megamind
Complete "Funky Disco" Level as Megamind
Unlock the Rampage mini-game as Megamind
Complete "The Sewers" Level as Megamind
Unlock the Mega-Ball mini-game as Megamind
Complete "The Underground" Level as Megamind
Complete "Demolition Site" Level as Megamind
Defeat Destruction Worker without dying as Megamind
Unlock the Pod Race mini-game as Megamind
Complete "Downtown" Level as Megamind
Collect 3000 B.I.N.K.E.Y. in any single level as Megamind
Complete "The Museum" Level as Megamind
Complete any story mission without dying as Megamind
Collect 2000 B.I.N.K.E.Y. in any single level as Megamind
Collect 1000 B.I.N.K.E.Y. in any single level as Megamind
Collect 150 B.I.N.K.E.Y. in the Lair as Megamind