I'll give it a go.
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A level where you have no builders to use as a skill
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No destructive skills sounds like an interesting idea especially if you don’t have any blockers either, and containment has to be done by using builders creatively or something.
A level that is one-screen (where you can't scroll left or right).
No floaters and high attitude areas need to be descended with clever destructive skill use (or not).
A one in each rank level but each solution uses the terrain in an excepted way each time (where something that's used for decoration is suddenly used for a solution in a later rank).
A level where you have to literally think outside the box and go outside the established boundaries of the level to solve it.
A level where the stacker skill is used to make a staircase (don't know if that's possible).