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