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