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