Hello! No, the difficulty doesn't ramp up currently! It was definitely a feature I wanted, the problem for me was that scaling difficulty is really hard to get right without extensive testing to make sure it feels well paced and doesn't get out of control.

The advantage of wood walls over the bars is that the wood walls have more health and are harder for yetis to chomp through, but I agree that later in the game they kind of fall off. It doesn't matter how much health your base has if the yetis can never get to it!

Thanks for your feedback though, and I'm glad you had fun! :)