I finished the full version of the game and I have to say that I really like some aspects of this and others I think could use some work.
First of all the artwork is insane. The detail in the backgrounds, the colors, the little animations for the smallest of things like the rats turn around animation - all of it superb.
I like the level design in a sense because of the way you wrap around the game world and how spaces connect to each other. It never really comes into play in the actual navigation because it is quite rail roady (except for one section in the end but even that wasn't too much of an issue), but it gives a nice idea of how the two worlds are connected to each other.
The actual level design is a bit hit and miss tho. I am not the biggest fan of the endless enemy tunnels and strings of floating blocks that you need to jump on. The approach to the setups is quite linear in the sense that you always interact with the game mechanics in the same way. Some more experimentation would have been very appreciated.
There was never a platforming segment that I found really satisfying to beat even tho some were quite long without any checkpoints.
The character movement is also not really something that appeals to me personally but I can see what you were going for. I just don't like it when the jumps are this high and there is a lot of horizontal speed. It feels very frantic and volatile to me. Also I think the areas for grabbing ropes are a bit too small.
Keep in mind that those things I critiqued are just my take tho. This is clearly very well made and this may just not be the kind of platforming I prefer. The presentation, music and storytelling already push this a lot in my opinion. So ultimately great job.