Thanks for your feedback!
I started to programm a bossfight against mr unfair, but I didn't had enought time to finish it. I wanted to implement a story into the game, but I started to think about the story to late in the process of the developement, so it was to hard to implement a story.
I don't really know, why the game is so large, but maybe it's, because every building in the game is a own sprite and the sprites for the buildings are big. I didn't used a tilemap. Another reason is the music. There are a few hidden music tracks, that I didn't implemented in the game and high quality wav files are very big.