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