I liked what you did here! I like the looks quite a lot, and the mechanics work very well! I loved the idea of placing boxes to get a tactical advantages, but unfortunately you cannot use them for much right now (maybe they could be used to hide behind if there are ranged enemies?).
When I just started the game I was not sure what I was supposed to do, so I just started to randomly walk around a bit. I was happy to find some enemies I could fight :D Then I thought it was just an infinite arena kind of thing, but when I found one of the pillars I knew something more was up :P In the end I found all four pillars and finished the game!
In hindsight I now see the paths that are supposed to lead you to the pillars, but to me they were not very clear when I first played (but that might just be me). Besides that, I think a bit more feedback to the player could be nice. Such as sound effects or some flashy particles when you kill an enemy.
The upgrade system was cool as well (I just upgraded my sword to the max, and that seemed to work pretty well!), but you have to be careful not to accidentally click on it. On the other hand, it was really big and clear, so there was no doubt about what it meant.
Very nicely done, and a great submission to the jam! Thank you for making it, I enjoyed it :D