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