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