I quite enjoyed this, especially discovering the new enemies and what the next sword would be. I think there definitely needs to be an ending when you get to the final sword - boss fight maybe? Just something to make the game end (unless there was and I just didn't get to it lol - music just stopped for me so I assumed it was the end).
Also I gotta say, the sound of clicking that upgrade button feels like it's blowing out my eardrums every time haha.
Overall, a good game - kept me playing until the end. Well done.