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