This game looks intriguing to me, but one thing I'm not sure of is the Chainsaw Battles. How do they work? Are they quicktime events? Because I'm really bad at those, do they factor at all into single player? Would I be able to complete the game without engaging in one?

if it happens then you pretty much just mash on the x button, but it doesn't happen a whole lot in the single player campaign

It happened twice to me

Whenever you attempt to chainsaw an opponent who has his Lancer out, and you approach him from the front (or if someone approaches you from the front with a chainsaw and you have your Lancer out), a chainsaw battle starts. Then you mash B to win.
 
One boss in the game requires that you win a few chainsaw duels, but it's not that hard, especially if you're playing on normal. The only time I ever lost a chainsaw battle is on insane difficulty.

Slam on the b button I believe, and it barely happens so you should be fine....it happens in multiplayer a lot though

I think you need to be starting a chainsaw event for it to even pop up. It's no biggie, just button mashing as dutch42 said.
 
I like the single player story. Nifty science fiction.

The game is absoutely worth the purchase for this reason:

" The game is absoutely worth the purchase for this reason:

SPOILER WARNING: Click here to reveal AWESOME content..

A GIANT WORM?! THEY'RE SINKING CITIES WITH A GIANT WORM!

"

" The game is absoutely worth the purchase for this reason:

SPOILER WARNING: Click here to reveal AWESOME content..

A GIANT WORM?! THEY'RE SINKING CITIES WITH A GIANT WORM!

"

Yes you can complete the game without engaging in one, and they are incredibly easy to do anyway, so it doesn't even matter, you just mash the B button.

They are really easy to win in singleplayer. You wouldn't have a problem.

" Yes you can complete the game without engaging in one, and they are incredibly easy to do anyway, so it doesn't even matter, you just mash the B button. "