FIRSTLY I found the same bug I found last jam. 

Secondly, I HATE this game. 

Not to say that the game isn't good, but it's punishably difficult to the point that sometimes I feel cheated. There are some levels that just make you really frustrated. I got to the end game but I was so frustrated by the time I got there I just wanted it to end.  I had not more in me to finish the hidden levels I got to the mainframe hidden level and couldn't go on.

Now, This may be what you're looking to accomplish with the game. If so good work. But for more accessibility, you need to make the game a bit easier. @MewsSnep Comment explains some of the issues really good so I won't repeat it. 

Have you ever played The Messenger? 

I think you're trying to go for that kind of spark of exploration in the end game. But it feels kinda like a chore here.

Congrats on the progress you've made. Keep it up.

Going to point out some things I noticed while playing, and some of my thoughts. I hope it comes across as helpful and not nitpicky ^^

Menu:
-In the starting menu I couldn't see the "press space" at the bottom due to the screen size so I
pressed escape to exit the menu, which reset the game.

Tutorial/Level 1: 
-says press "S" but its actually "W" that works.
-I really didn't like how fast the character felt here (I think is just because of how small the screens are for this area)
-Nice reset, very fast so dying didn't feel tedious

Hub: Level locations feel a bit all over (but that's probably going to be different for everyone just for me I was looking for level 3 and it was the last one I went to lol)

level 2:
-Some platforms that look the same have collision from the bottom where others don't.
-Didn't realize I could jump on the grabbing points.
-Nice job on the coyote time
-Was one section where I could of died after the screen transition but before the checkpoint (would feel really awful to beat the section only to be reset because the next section killed me before the checkpoint)

Level 3:
-There was another couple areas where I could of died right after the screen transition to the next section
-The moving platforms don't have any visual differences between fast, and slow
-I had trouble seeing the button on one of the levels
-That last screen was a doozy XD

Level 4:
-There  was a screen where I nearly walked into the red just barely missing the checkpoint
-the swinging with reversed gravity doesn't feel right to me
-Last screen was brutal again :P
-(For some reason I had to redo it because it didnt count as completed later)

Level 5:
I ended up in the floor (I believe its based off the grab the corner mechanic)
The part where you're being chased by the wall was a frustrating part, I thought it was impossible and then through I got stuck in the bottom area but luckily I could just reach the button, that being said the hint wasn't very helpful and might even give the wrong idea but I did manage to figure it out after a good bit of trial and error, only to be killed by the opposite wall just before reaching the checkpoint)

End Game:
I was frustrated with all the puzzle platforming that when I got to the end I did not want to think about it. Sending me back through the levels felt like a chore luckily it wasn't that difficult to figure out but after everything else I quit during what I assume to be the end climb back down.

Overall the game felt like a rage puzzle platformer and the reason I think I feel that was is mainly due to the trial and error that has to go into everything. Was still a fun game for awhile, but it left me wanting to feel more in control. If a hard puzzle platformer is what you're going for then you've done a good job at it (Maybe throw in a death counter for an added insult to injury :P), but if you're looking for something more accessible then I think some changes might be needed.

Game Maker's Toolkit did some videos on platformers that might be helpful to remove some of that frustration building. Regardless though, with a bit more polish I think its a very solid game. Nice Job.

Just remembered I took a screenshot while I was playing of when I got stuck in the floor

-The running mechanic makes precise movement hard

-I'm not really used to using space to jump, maybe an option to remap the controls?

-My PC cant see all of the screen

I'll probably finish the game given some time, here's some level reviews

-The Vault

Checkpoint 2's laser can be bypassed by running to maximum speed after the laser has just gone out

I didnt see the sling the first time i played it

Checkpoint 5 requires you to be precise, but this is a tutorial it shouldnt be this hard