Hi there... the graphics are nice, but I guess you didn't do them while the jame? hehe
First of: I highly suggest webbuilds, as many players wont download games for jams. I just did because I promised it, else I wouldnt... mainly because of possible virus, but also because of lazyness...life is life! :)
About the game:
One can see that you put a lot of effort into designing the level... did you do platests yourself? Sadly the design has quite some flaws that in the end even stoped me from finishing it.
Let's begin: You seem to have some random factors. The first (and probably all enemies?) Has a random spawnpoint. This can be quite unfair depending on the point.. no need for it to be random imo. Also you didn't introduce him, like you did the jumping and the sliding. Btw. you can jump over everything... therefore no need for sliding.
Critical random factors are the plattforms. Depending on the timing you might come there without a plattform there, which contradicts fast gameplay if you have to wait for it...additionally many players will jump into the blue expecting something that they can't see yet.
The problem becomes more critical when you combine the plattforms, standing on one and reachign another means their timing has to be even better!
And the problem evolves if you have a spawn point in air which simply drops you while there is no plattform around and therefore throws you into certain death...
So far so good. I went on until the (3rd?) floor ig, meeting new enemies, which is cool, even if they made no real difference. Double jumping was introduced, having no time to read it I had to imagine that it was ment to be double jumping at least. I tried it, used it, succeeded, for a bit... until I met walls where double jumping was rarely helpfull and it became a thing of luck if you can climb the wall or not. Running (which was never introduced) helped a bit, but not really. I had to stop there...
Try to be a bit more friendly to the player! ;)
Noone likes to be punished for things that they can't influence or that simply feel unfair and noone wants to stand in front of a wall trying to jump it 100 times in hope to reach the edge.