Cool idea and a great execution of it.
The art style gives off a pretty creepy, lonely, sad, melancholy vibe which contrasts nicely with the expected joy of riding a pogo stick. Also the little trees and the smile at the end are a little injection of happiness.
The jumping around was quite satisfying. It seemed like you moved around at just the right speed and your jumps were just the right height. The jump was a bit higher than the platforms so you could be a bit imprecise with your jumps and still make the platform.
Your level design was interesting and seemed well thought out for the most part. You made use of the fact that you pogo up AND down so there are hazards whether you are jumping or landing which is really taking the design space of the forced pogo stick all the way. The levels themselves were a bit too hard, however. This was mostly due to how long they were. I would figure out how to beat the first jump after a try or two, then make it to the next challenge, then fail and have to retry the first challenge again. So the game was a series of corpse drags where you have to beat the whole level just to try again at the last jump (the spikes on the roof of the second level took me forever). I would have preferred if the levels were basically cut in half and you just had twice as many levels. I think that would have been about the right amount of time per level. Something like that or having checkpoints in the levels would be handy. Or just if the first levels were basically one screen, then the last 1-2 levels were as long as they are now. I'm okay with trying a 10 seconds section 100 times, but retrying a 30 second section before the 10 second section 100 times gets a bit taxing.