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