The more diligent among Doom Eternal's completionists have already found every collectible out there, discovering that the title grants them a few extra Sentinel Batteries in the process.
In fact, Doom Eternal seems to have more than required of each collectible used to unlock powers and cosmetic items for the Doom Slayer. Here's what we know about whether or not the extra sentinel batteries can be used for something at the moment.
Doom Eternal Extra Sentinel Batteries
Sentinel Batteries are used in unlocking the upgrades and armors locked behind various gates in the Fortress of Doom.
Each gate requires two Sentinel Batteries to be opened, which makes the collectibles rather valuable, particularly if you want your Doom Slayer to don an armor similar to that in the original title.
Players who've collected everything Doom Eternal has to offer have, however, found that they're left with 4 extra Sentinel Batteries. But is there a purpose for them?
From what we can tell, the extra Sentinel Batteries don't have a set purpose at the moment. They could simply be there because the developers wanted to make it easier for players to unlock all the cool armors in the Fortress of Doom.
Fans are also speculating that there could be a purpose for the four extra Sentinel Batteries in the two upcoming DLC packs that Doom Eternal is set to receive later this year.
Lastly, and getting a tad conspiratorial, it's also technically possible that a super-secret area alongside its super-secret rewards still lays uncovered in one of Doom Eternal's levels, although we see the previous explanations as much more viable explanations.
Doom Eternal is out now on PC, Xbox One and Google Stadia. For more help with id Software's latest effort, check out our guides on the unlock code for the old PC found in the Fortress of Doom and the Super Gore Nest collectibles.