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