very nice idea with a big potencial. I enjoyed this game :)

pretty nice game, even if i got some issues with the interface / inventory:
-i found the inventory system unpractical, as you have to open it every time you want to do something ( wanted to destroy some cristal ==> "I", select hammer, "I" again to close the inv; Then i want to open a door ==> "I", put hammer in inv, "I" to close, click to open door, ...)
Ofc you can just keep your tool around, and drop it when you want to do something, but well...
-a little feedback effect when you get hurt would be great ( screen flash or sound effect)

Besides that, even if all the movements are a bit rough (the player teleport each time you move), the graphics are quite cool, and the game quite enjoyable.

I think the inventory and control method could use some improvement, it was a bit frustrating to select and use things. But there was a nice sense of exploration here, I liked that you have to discover things on your own. I enjoyed playing it

I like the way of exploration but gameplay lacks of goal and input needs improvemtn. How about switching items by pressing hotkeys 1-9 like it was made in Minecraft? Openning interface and pressing hammer to dig crystals every time is a bit annoying, espacially when you can't fight with it or open the doors with hammer in your hand. The better way to do it, is by choosing your current equipment (e.g. hammer) and fight, openning doors and picking crystal by movement --> WSAD. It's more intuitive and less frustraiting for players who won't have to open/close inventory each time he want to do anything. Also adding system of fighting could improve gameplay and procedurally generated world is the way to increase gameplay length.

Well, I found it kinda confusing that you need to use the mouse to pick and use itens when it's said that you can use the "I" key to open the inventory. I thought I could play it using only the keyboard, pnly after reading the other comments I understood that I had to use the mouse.

Other than what has already been said, the hitbox is also quite imprecise. I'd often miss the slime even though I was clicking all over it...

Since there's no real use to the mouse, other than inventory management*, you could easily map the action to a keyboard key. (*aiming the gun could be handled by the direction the character is facing!)