Forgive my late reply, I just wanted to comment on the fact that as a level artist, I once attempted something very similar to your first screenshot as an attempt at some asian styled temple and I believe many others before me have as well.
As for critiquing...
- First level is an excellent attempt as building something outside the boundaries put in place by the default tileset. Do not attempt to expand on that particular style however, even at its best it could be done better with custom tiles.
- Second through fourth levels look to be an attempt at emulating the UN style of house interiors. I don't understand where this style even came from, I guess some people believed that the complexity of a level equaled quality (they were wrong). Truth is, you can make some great interior levels with what is provided (see Wan's work if you want examples).
- The last level I cannot really comment on since it looks like a test level, but I will emplore you, going forward make sure not to fall back on tree images (or any image) for quick tiling a level. For one, it is more stressful on the client, and for two it looks terrible when you actually take a closer inspection of the level.