First off I love the art style, it is super cute and I think you fit the theme really well with the narrative! The music fit extremely well too and was super fun. What you've managed to do in the timeframe is super impressive! I will say on my first few tries I was super lost when it came to gameplay and what I was supposed to do. I think for the future even a simple explanation of controls in the description would be a big help!
That said, when I did figure it out I enjoyed it! I love tower defense games and this has tons of potential. If you were to continue working on this I'd suggest shrinking the particles or playing with the transparency as they got very overwhelming and intrusive very quickly. The only 'bugs' (haha) I encountered were the music cutting off and the game just freezing at some point, otherwise a pretty smooth experience!
Overall this was super solid, I would be excited to see a polished version of this in the future! :D