The Chainsaw is a returning weapon in Doom Eternal. It functions the same as before, ripping and tearing open enemies to spill ammo and guts. The difference is that it automatically refills 1 gallon after being fully depleted, and it holds only 3 gallons (originally up to 7 in Doom 2016), but its low fuel count is made up for in brutality. Fodders and the Tentacle take one pip to chainsaw, Heavies take three, whilst Super Heavies and Ambients other than the Tentacle cannot be chainsawed.
The Chainsaw is much more integral to the gameplay than its predecessor in Doom 2016: while it is weaker compared to its predecessor, the Slayer has very limited ammunition resupply options in Doom Eternal, limited only to pickups and shotgun shell resupplies from killing units with a fully upgraded Full Auto Mod outside the usage of the chainsaw.