There's a lot of potential here. I can tell you put a lot of thought and care here. Instead of criticism - I'm going to provide some thoughts I had:
- I like the music and the art on the pigs. Music needs more punch to it and cleaner looping would be fab.
- The different weapons - great implementation
- I didn't feel there were many stakes. I could walk into a crowd of enemies and get them all. I think knockback or stun may make this a less tempting but not unviable if you invest in miasma.
- I had some performance issues around level 13. Too many pigs on screen?
- I found myself walking in a circle. I wonder if varying the environment could make this les viable.
Again, potential. If you iterated on these ideas, there's something to be developed here. You should feel proud of yourself.