Thanks for the feedback! One thing to note, in case this was the issue, is that only the tiles you touch during nighttime show up during the daytime (and they disappear over time as well). So you can kind of control how full/sparse the daytime version of the level is by how many blocks you hit at night. So often the best strategy is to go slow at night and hit a lot of blocks, and then backtrack quickly during daytime.
Thanks again for giving it a go!