I wish you luck with the project. At the moment though, there's not much there.
There's of course the environment which looks very close to Minecraft, so kudos for that. You can mine things and move around, so the basic feel is there, too.
The procedural world generation needs a lot of work. You should ideally prefill the seed field with something (so people don't have to invent a random sequence of letters) and ensure any seed generates something sensible, *varied* and gives you a good starting location. Perhaps I was just unlucky.
My first experience with the game involved falling in the middle of the ocean, which had mostly uniform terrain. Not very fun to spawn in a fully blue screen.
https://www.newgrounds.com/dump/item/bc91f567aac8111f3849124b91e24492
My second try had me spawn on top of a tree – and there were hills with many trees in every direction; not much variety. I was eventually able to reach a beach, so at least there are biomes.
Water physics is funny. You can swim in water, but if you're not too far from the shore, you're walking on water, and can mine water. Water doesn't flow in any way, so you can create an empty block in the middle of a body of water. If you dig through the seabed, you can stay dry and mine water from underneath.
https://www.newgrounds.com/dump/item/b37dfdb1bad7d394bc4c86082a332e4f
There's not much to mining, you can mine a lot of things, but that's about it, not much to do with it, no crafting or building yet.
Main Menu – entering Options and clicking Done crashes the game. Having a Quit button in a browser game is also pointless because all it does is crash the game too, but you're still looking at it in your browser window. You're not closing anything and if you'd like to, you'll just close the tab.
Of course, I'm pointing out things you may very well be aware of. The game is a good technical test, but there's not much reason to “play” it yet.
I am very curious about how a “survival horror” RPG would work in this Minecraft style.
I would be worried it would either not be scary enough in this style, or I'd be aimlessly wandering in a procedurally-generated world without a goal or reason to continue playing (i.e. if everything is random and I begin with access to everything, there's no reason to expect something unique or interesting further down the line).
So I hope you get to see it through and make the game you envision.