Hey thanks for the feedback! Having deckbuilding choices before the missions is a fantastic idea, and yeah getting a hand of all stone walls really sucks.
We're actually about to put out an update that changes the structure of the game and hopefully will really improve on these aspects. At the start of each level you'll use your whole deck to build your castle and then the enemy waves will be much shorter, just a few more intense waves. The deckbuilding will be between levels. We have a new map and map gameplay too!
If you have a chance to give it another go after we get the update out in a week or so we'd love to hear what you think. Thanks again!