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