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