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