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