Here is the full list of all 30 Disgaea PC achievements.
Dealt 10,000,000 Damage!
Completed Final Episode of Etna Mode "Chronicles of Etnarnia"
Completed Ep. 1 of Etna Mode "Super Dimensional Etna"
Completed Final Episode "What Lies Beyond the Battle"
Defeated all EX bosses!
Completed Ep. 10 "Angels, Demons, and Humans"
Performed 10 transmigrations
Obtained the Hyperdrive!
Defeated the Extra Boss "Baal"
Defeated the Extra Boss "Item God 2"
Defeated the Extra Boss "Item God"
Obtained Total LV 10,000
Defeated the Extra Boss "Marjoly"
Obtained Total LV 5,000
Defeated the Extra Boss "Priere"
Dealt 100,000 Damage!
Cleared Extra Stages "Cave of Ordeal"
Defeated the Extra Boss "Item King"
Obtained 10,000,000 HL at the end of battle
Obtained the Dream Hand!
Obtained Total LV 1,000
Obtained Total LV 100
Obtained 1,000,000 HL
Completed Ep. 5 "Etna's Secret"
Performed your first transmigration
Killed 1,000 enemies!
Killed 500 enemies!
Defeated the Extra Boss "Item General"
Completed Ep. 1 "Prince of the Netherworld"
Killed 100 enemies!