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