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