The starting UI is pretty polished. I like the lights changing to red when hovering over Exit. The display of the controls is nice. There is a typo in "Controll". It should be a single "L".
I like the jump state indicator at the bottom left.
Starting out, I did not expect touching the pumpkins to kill me.
The "Dead" screen feels like it takes a bit long. I suppose that may be due to things reloading, but when trying to get through an area and messing up, I want to get back to trying quickly.
I do like that you have plenty of checkpoints. I'm not particularly good at the game, so only having to do each section on its own allows me to play further.
At the first platform you press "E" to use, on a retry I double pressed "E". It gave the sounds acknowledging the inputs and stayed down. After that it did not want to respond to pressing "E" again. I got off an back on and jumped. Finally I ran back to the door and after that it worked again.
I really struggled with the area after that. It felt like my jumps were launching me forward far more than I expected and I was not able to land on the first platform. I finally got through by just trying to double-jump as far as I could across, landing on the last platform and finishing getting across before the attacks hit me.
The breaking platform by the keys in the next section was a surprise. I was happy I had gone to the left side first and did not need to redo that last area again to get both keys. Still, I decided to check, and was surprised to see I could still interact with the platform to bring it back down. This is convenient and makes teaching the breaking platform mechanic here work well.
Getting to the next jumping section, it again feels like once I'm in the air my movements are massively exaggerated and hard to control. A simple tap and I'm flying across the screen. Personally, I think the movement when in the air needs reworking. Once you are in the air you would not normally have as much control over your movement, whereas here you get increased mobility. Sure, in reality you can't double jump and games don't need to follow reality, but the faster movement in the air both feels wrong, and makes it harder to control the character. For me, this lessens the enjoyment of the game.
In general, this game feels very dependant on double jumping. The basic jump doesn't feel like it does enough on its own for most places you need to jump. The double jump is a fun mechanic, but I do feel like the basic jump could be used more on it own to make the double jump feel more valuable.
I cleared the section where you jump up past side shooting pumpkins, paused to type the above, then jumped onto the next thing. Something flickered and then I got a message of "I told you idiot". I'm not sure what I missed, but I did not like this interaction. Whatever flashed was probably instructions or a warning, but it was not on the screen long enough to read, nor did it appear in time to let me know to stop before jumping. Rather than the game mocking me, I felt this should have been reversed as the game did not warn the player reasonably about whatever it was mocking us over. I went back through and moved slowly. The only message I got was to press "E" when I landed on the platform that raises. I jumped onto and off of the grass that falls, but still did not see any warnings. I intentionally walked back into the lower area and got the same "idiot" message. Maybe the first time the thing that flickered was the press "E" message as I had touched the platform before falling back and ending up in the lower section. So, I'm now wondering what the "idiot" message was about. I feel like there should be something else here to warrant the message, and to explain why the grass piece fell away.
While I am slowly getting more accustomed to the controls, I'm not a fan of them. So much of the game is double jumping, and the excessive movement while in the air is just not something that works for me. So, this is where I ended my playthrough.
You have a pretty good core here. The level designs seem decent. The core jumping mechanic works. I'd personally like to see some refining of the controls, but that is my preference and the controls may be fine for others.
One other recommendation is that a web version would be a good choice if you want to get more feedback from jams. A lot of people will not download games to play in jams.