Lots of negativity coming right up, don't take it the wrong way though. This game looks great and I hope you improve it for the final release.
I loved Crooked Silence and I was really looking forward to ruptured but I gotta be honest with you; those climbing vines at the start of the demo almost made me quit right then and there. They might be the worst functioning ladder I have ever seen in any game I have ever played. You fall right through them unless you stop your momentum at the exact right point which is extremely frustrating. In fact, the whole jump to climb thing feels really bad on normal ladders too. What you'd need to do would be to make the vines solid so you smack into them, and have forward also act as climb so you climb as soon as you touch the vines.
Other things I noticed:
The game crashes on startup if you choose fantastic as graphics preset.
If you alt-tab it freezes.
Very low mouse sensitivity.
For a shooter with this aesthetic it is quite slow on the movement speed.
Whenever you enter a room every enemy seem to be aggroed right away and swarming you.
Weapons don't switch when they run out of ammo.
The jump seems to not always work, I think it's because your edges are literal, in most games edges are programmed to be a little further out than they actually are when it comes to jumping so that you don't have to look down to make sure you're not a pixel too far out.
If you stand right against something and try to jump onto it your jump seem to be much lower than if you walk a bit away and then jump onto it.
Now this all sounds very negative and I will admit that I didn't have much fun and didn't even finish the demo because of it. But I do love what you are aiming for. I love your use of color and I extremely love that you have enemy infighting.