Do you get a loop in Charles's conversation? If so, that's a bug that has been fixed in the patreon version (it doesn't affect those who flirted with him during the quest, which is why it escaped notice before). If that's not the case, instead, make sure to tell me what's the issue, maybe I can fix it.
I have been thinking about how to modulate puzzles and their difficulty. Right now it would be kind of hard to go through Caliross and change stuff, but my ideas would be useful in future games. if you have some specific puzzles bothering you, I can see if I can maybe add some options to ease the difficulty, or allow to skip them.
I think generally it's easier to have a more costumizable challenge if you plan for it from the start. I like puzzles, but since I personally started to hate mazes, I can see why some allowances should be made.
On the plus side, TOTDC 2 shouldn't need tweaking, because usually the quests have multiple solutions, and often there is a "just shoot everything that moves" approach.