Hi,
I thought this was very challenging, I think the balance is way off at the moment, and it's not clear quite what you are meant to do at first. The enemies take too many hits to go down and they are also too fast, at least at first.
I could not see the feedback for hitting the enemies in the browser version - I didn't realise that they went a different shade of red until I played the windows executable version. I think that maybe you need to have some sounds and effects to sell the sword swing and the hits, and maybe add some knockback to the enemies.
I also found that in the shop you can click the items that are available for purchase but it will not buy them and I had to press space, so I was quite confused why I had the five souls but could not buy the ally.
I thought that the timer for the in-between waves time was quite good at creating a bit of tension of kinda "oh I have to be quick in the store"
Excited to see how this develops in the future!