Building UI ajustments
there needs to be a bar across the top (or bottom) of the screen that fills up as you add traps to give players a visual gauge on how much things contribute to difficulty and how close they are to pushing their base into the next difficulty
currently for blocks, each blocks is part of a pack, get rid of that. players dont want to be limited to what blocks they can use due to the arbitrary categories you have put them in. this will also allow you to remove the icons that add clutter to the block pictures (you also repeat info on how much an item costs to place twice on the screen adding again more pointless clutter), instead do like you have done for guards, traps and decals where you can have so many unique types
it should be set so players can only use so many unique block types (and decorations) per map, so 10 unique blocks and 15 unique decorations. that way players can be as creative as possible, this will also make the integration of future dlc into builds easier should u want to use existing blocks but then the decorations from the dlc.
the current 'packs' system is frustrating and needlessly restrictive. (anyone i have asked about them agrees they are stupid and that they just add more friction to the building experience)