Is combat necessary? Or can it be played as pure tower-defense?

I like tower defense and might buy. I detest button-mashers and never buy.

Combat is necessary. The combat usually involves abusing traps to soften up enemies and using fear to keep them from attacking while you beat them to a pulp though. I actually enjoyed the combat because of the strategy choices that were given. for example, yelling and then hiding to lure enemies to where you were when you yelled, and then releasing a trap above the enemies heads that crushes them with rocks.

I found the game to be difficult in the middle and easier near the end due to the power of some of the later traps. But if you play around with traps you can actually beat a lot of the levels with minimal hand to hand combat.

Despite what you read in some reviews, I found the combat enjoyable. It has a lot of stuff you can use to your advantage. It makes the combat less dexterity oriented, but more tactical. Hard to describe, if you haven't played it. However button smashing is part of the game. Combat usually is click, click, click, dodge, wait then do it again and reloading the rifle is speed up with hammering the right mouse button. (For which I made a macro)

The game is build in such a way, that you have to play your route in respect where your enemies are. For example, lets say there are some enemies attacking the barn, the house and the mill. You might want to battle the enemies at the house first, so you build some traps to dispose of them more quickly. Then you move to the barn and battle the enemies there, however you have to plan to delay the enemies which go for the mill with ,for example, bait or firewalls, so that you can get there in time.

In a nutshell, you are planning a combat route and build traps that suit that route. It's not the other way around that you build traps and go to combat where they fail.