I played something like the first dozen levels of Soulcaster (1) and it seems interesting and fun. It's almost reminiscent of a tower defense game since you place units down that do not move, and they need to stop the monsters from reaching the target (you!). You're pretty much defenseless on your own. So there's some strategy in placing your strong units in front to block enemy passage while using ranged units to bomb from the back.
It's not exactly a tower defense game. And since what you need to protect (yourself) is mobile, there's not necessarily one specific way to beat any given level. Also, as you move around the map, enemies will spawn from different places. And sometimes the map changes (e.g. walls break down or bridges appear). So it's actually fairly difficult at times.
As for Zeno Clash, I bought it and beat it back when it first launched. I really loved the concept, story, art and sounds. Actually I really loved pretty much everything about the game except the combat. Maybe they've fixed it since then. But so much of the game is just purely combat, which is hard, punishing, and felt unfair to me at the time. Like my character wouldn't do what I was trying to get him to do. I had to fight several battles over and over and over several times. I probably "ragequit" a few times. The only thing that kept me going was that I wanted to find out what happened in the story and see more of its universe. I can't remember if there was an option to turn the difficulty down or not when I played it.
I'd love to revisit the world and the story, but I've been hesitant to put myself through that torture again. It might be worth another playthrough on an easier setting. Sometimes I wish games would unlock a video mode after you beat them, so you can just watch the whole thing like a movie to get a refresher on the story without all the time and work involved.
EDIT: One thing people complained about at the time was the poor translation of the game, since the developers are not native English speakers. I actually didn't notice that it was a poor translation. I thought the people just spoke somewhat oddly because they themselves were somewhat odd characters. In my opinion, it actually added to the charm and mystique of the Zeno Clash universe which is a quirky and strange place.