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