1. Has potential but it lacks something - not sure what. It's a fun pic though.
2. I like it, it make me smile.
3. Again, it lacks something. I assume the subject is the sun but while the building is kind of cool, it's just not working for me with the composition. Nothing really draws me in.
4. I would have used a lower angle, get down with your subject at their level. Shooting down on the butterfly really isn't very flattering. Also, there's a white balance issue, there's a yellow cast in the image that could quickly be cleaned up in PS or Lightroom.