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