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