The instructions need a bit of work. It told me to left click to dig, so I tried that and nothing happened. It told me to right click to use a weapon so I tried that and nothing happened. It took quite a while to figure out that I needed to (a) construct a pick & a sword first; and (b) equip them, before I could carry out those actions.
The text saying "set your recipe by left and right clicking on materials" never disappears - after it appeared, it stayed on my screen for the whole playthrough. I tried closing the browser tab and opening it up again in a new one; same result.
I found I could click on blocks that I couldn't actually reach & they would still disappear.
The aim of the game was never explained. Am I trying to get as deep as possible? Am I trying to collect something specific? Am I trying to find materials so that I can craft something special? Without that it all felt a little pointless.
That's quite a few negative points, but don't get disheartened: I've only been able to comment on these things because you got far enough along in making the game to begin with. That's more than a lot of the entries I've played!
Also, I really liked your music & thought the graphics were well done: that vignetting really suits this kind of game. You got quite a lot of different game systems implemented & working within the time as well, which is impressive.
I think my advice for next time would be to try for fewer gameplay elements but spend more time polishing them. What you have here is good, but feels rough around the edges.