Bethesda did not reveal a sales number but has said the game reached 3 million players faster than Doom Eternal.

The upgrade system in Doom: The Dark Ages splits between attribute upgrades and equipment upgrades. For the former, you need to acquire Demonic Essence and they raise your Ammo capacity, Health, and Armor. On the other hand, the latter involves visiting Sentinel Shrines and spending resources to make your favorite pieces of equipment stronger.