Okay, this was probably one of if not the best submission so far... First of all, the art style: The cool background art with parallax effects, and the shines of the sun through the trees, amazing... The kingdom, the archer, the monsters, and the arrows were also very pleasing... The upgrade menu was also well-designed, nice to look at, not overly cluttered, while being easy to understand. Next, the gameplay loop was also pretty fun, nothing I've never seen before but definitely well-executed, and challenging enough that it's fun. What made it even more fun is the upgrade system, where you can become super overpowered in a matter of seconds! (maybe an over exaggeration but you get the point).
Now let's talk about the tax system, absolutely incredible... A clever way of making the game include more strategic thought into it, whilst at the same time adding another layer of difficulty curve. This was honestly a pretty surprising thing to see in a game jam, but it probably follows a textbook rule from somewhere out there, and it's implemented hella good. Next, the audio, the ambience with birds chirping and such, very soothing to listen to. The shot of the arrows deliver weight to them, and the impact of them on the enemies carries so much JUICE.
There isn't much negative things I could say about this but if I absolutely had to mention something that could be made better is the screen shake. It made sense with less arrows, but when it came to the later rounds, it got pretty chaotic that the screen was never still. Also, a boss would be nice, but taking into account that only 3 days were put into this, this already had plenty of content to be content with (pun intended).
I don't know about the other comments, but to me, the difficulty was fine, it was challenging but fun, (the randomness in the arrows was not a problem considering an upgrade could situate that), up to a certain point where I had all the upgrades and pretty much have nothing else to do, no enemies can even come close unless I purposely lose (which I did when I had like 200000+ coins, sad the knight costs way more than that). If you were to make this into a full game, which you absolutely should if you want to, I think difficulty options needs to be added. To be quite honest, this game has the potential to be a quite successful maybe mobile game, or pc game. I'm thinking if you could make it fit into the roguelite genre, it would absolutely SLAP. Just add a bunch more content and polish and you have yourself a possible indie hit.
Ok anyway this review is getting quite too long. Great game, loved it!