Very lovely game! I thought the challenge level was just right. I had to take a first run to get the hang of things. After a tense few waves, I got upgrades and the difficulty flattened out. Around wave 5, I think I had enough health that surviving the wave was no longer very hard. All the same, I enjoyed it! Very charming art and audio!
I noticed a bug when shooting at the rock throwers. If you aim around their feet, especially when south of them, arrows from the crossbow appear to get lodged in an invisible barrier and they do not take damage