In this game you start by mining water, then you can turn that into kelp and you can turn that kelp into kelp planks, find, the other things by yourself. :)
This has nothing to do with the game called Limbo.
There's no indication on the page that this game is a work in progress, but it seems to be incomplete to such a degree that there's no real point for folks to play it.
I got through a bunch of crafting recipes and couldn't really find anything interesting to do in the game aside from putting items in various shapes on the crafting grid. To make sure I wasn't missing anything I checked the code, and indeed--there are:
Several types of nodes, all of which are completely static and have no functionality
No tools (there is technically a fishing rod, but you fish by uh... putting it in the crafting grid with a solid block of water)
A number of items that either do nothing, or restore the health that you'll never lose because there's nothing to lose it from besides deliberately hurling yourself off of a cliff. You can't even drown!
No biomes or structures, only the bare minimum of mapgen aliases
A bunch of crafting recipes
That's all there is. It's a collection of convoluted crafting recipes that goes nowhere. It's not even good for building, since most blocks require multiple stages of crafting and a fair amount of resources to produce.
The game might be good someday. It might be a game someday! But today, I don't see any reason to interact with it.