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