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