Yep, that's how I felt, too, once it clicked. I think I'm going to go on Steam and start a thread complaining about being forced to use guns.That's weird. I mean, a lot of the stronger demons have weak points you can exploit but the old adage remains true: if brute force isn't working, you aren't using enough!
As far as the chainsaw goes that is an adjustment. But once you get in the habit of wacking a mook with it every few kills it's fine. The thing recharges a single use now and you can collect gas to attack more powerful enemies.
It took me a few missions to get used to the new systems - the dance of farming resources while killing enemies is significantly more intricate - but at some point it just clicked.
I am become death, slayer of worlds.