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