Here is the full list of all 30 Fallen achievements.
Control All Zones in Ground Control Map 10
Score 1 in Death Race Map 3
Score 1 in Death Race Map 4
Score 1 in Death Race Map 8
Score 1 in Death Race Map 7
Score 1 in Death Race Map 9
Score 1 in Death Race Map 10
Score 1 in Death Race Map 5
Score 1 in Death Race Map 2
Score 1 in Death Race Map 6
Score 1 in Death Race Map 1
Pickup Walls Power up in King Of The Hill Map 8
Pick Super Bat Power up in Pick That Pumpkin Map 2
Die in Spikes in Head Hunters or Last Man Standing Map 3
Pick Risky Pumpkin in Pick That Pumpkin Map 7
Use Teleporter in Pick That Pumpkin Map 3
Hit Red bat in Pick That Pumpkin Map 1
Control The Hill in King Of The Hill Map 1
See The Beast
Meet Charlie
See the Reaper
Encounter 1st Ghost
Kill First Boss
Enter the Grave Yard
Kill Demon King
Meet Master Yuka
Witness the death of Master Yuka
Kill Masko
Play Level 1 of Spooky World
Play Level 1 Of Jungle World