Hey, thanks for the comment!
Sorry, there's no fullscreen option because I encountered some issues when switching back from fullscreen to windowed mode :S. I had a time limitation to finish this project, so I didn't invest much time in this issue.
I'm planning to use this game as a prototype, incorporating all the feedback I'm receiving. The idea is to create a new version with more stages, an actual story, enemies, traps, etc, and additional options (screen modes, difficulty levels, save game feature, etc).
Have a nice one.