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