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