I will have to be painfully honest here. This game is way too bland, and I don't think anyone would be able to stand 60 levels of this. Firstly, there's no objective. It's a pointless platformer. Demo or not it is still very average, with no redeeming quality whatsoever.
It is also not very challenging nor is it interesting. The challenge only comes from the awkward controls. Why have you programmed space bar as the jump button when W would have been a better choice? Was making awkward controls the only method you could implement to make the game seem hard? Also, where does it lead? What is the story behind it? There's no point to any of it all, just jumping a bunch of boring very uncomplicated platforms.
If you're going to make 60 levels of this, it's better not to. Unless you can make something much more challenging and interesting. This game as it is now is not very good at all. Please make better games in the future.

I liked the gameplay, and I really like the paralaxing background.

If I had a suggestion for the upcoming game its that I hope you might be able to reduce the slide when the character jump and lands. You know how when a character lands and keeps moving for just a little bit, if you could reduce that, it would be better.

Sound effect is cool, but more would be nice as well as a neat song.

Actually pretty good for a demo! There are a few glitches but nothing game breaking and other than that its actually good.

Can't seem to jump past the first green block thats midair.. maybe tone it down a bit.

The game was fun at first but then it felt tedious and annoying. The graphics could do with some improvements too. Overall it is okay. Keep up the good work.