We're only into week one of the rotating list of 'Mutations' coming to Left 4 Dead 2, but the code-burrowing Steam forum goers may have already dug up a good portion of the 20-plus game variations coming.

We know that "Realism Versus" is legit, as is "Chainsaw [Massacre]," but the list is full of placeholders, so set your expectations accordingly. "No Health Versus" and "Vip Target" sound like the kind of tension-filled fun that we're hoping for from Left 4 Dead 2's new expansion, of which we already identified Mutations as one of the add-on's highlights.

Here's the full list.

Chainsaws

First Man Out

Four Swords Men

Hardcore

Head Shots Only

Last Man On Earth

Linear Scavenge

M60s

Max Specials

No Health Versus

Realism Versus

Temporary Health

Ultra Realism

Versus Survival

Vip Target

List of all Mutations (Found in the VScripts) [Steam Forums via Dtoid]