I'm finding it rather difficult to launch attacks in DK1. I'm on something like the sixth level, where you first get the torture chamber.

Usually I would just toss a bunch of troops at the enemy, but you can only do that on your own territory. There are a bunch of reddish "path" tiles which say "unclaimed", but my imps don't just randomly claim them, so I can't really do anything. I can't quite figure out how Call to Arms works. I tried to cast it, but as far as I can tell, it does nothing except drain all of your gold, and now I'm bankrupt. About all I can do is possess troops one at a time for brief suicide runs.

The faqs I've skimmed through don't seem to address things like this at all, and if the earlier levels supposedly explained how this works, they did a bad job of it.

Is there a way to capture tiles manually? The torture chamber and all of the path tiles around it were "unclaimed" for a very long time, and the imps wouldn't claim them even if they were idle until the entire room was completely cleared out, which took a long time.

I'm finding DK1 pretty counterintuitive and the interface is out to get me. Apparently it's just me, since I don't see other complaints like this much.

unclaimed tiles must be adjacent to your land to claim them, so build a bridge to them,
(or if they are next to your land, just possess an imp and do it yourself.)

in dk1, the call to arms spell has a limited range, indicated by the size of the expanding red circle.
you can charge it you to extend this range by holding down the left mouse button before casting, but the significantly increases the cost, (from 1 gold/second to 9

Ah, thanks. That's the issue. Now if only they'd just claim tiles as they mined instead of waiting until they cleared a whole room first... :-/

This game really needed a mana system or something. Gold for everything is kind of absurd.

what you could do about that is pick up an imp then drop it in an unclaimed space with at leastone claimed square near it and no marked dig areas beside it to get that one to start claiming areas