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