Don’t train additional SCVs before purchasing Han’s contract in the “Cutthroat” mission on Hard difficulty.
Complete all mission objectives in the “All In” mission.
Complete 20 missions in the Wings of Liberty campaign on Hard difficulty.
Kill 50 supply worth of units within 15 seconds in a Melee game.
Destroy 15 Infested structures at nighttime in the “Outbreak” mission on Hard difficulty.