Looks good! But, I have some criticism for you.
-There is very little gravitational acceleration. Your character jumps and decelerates at a seemingly fixed speed. Normally when you fall, you gradually pick up more speed; it just looks odd at the moment. So yeah, definitely increase that acceleration. It looks entirely too easy at the moment
-The scrolling is so slow. I could see it getting really boring, really fast. Pick up that scroll speed and add a bit of challenge and fun!
-Your character isn\'t colliding on the floor properly, he is just sort-of floating there, again, looking odd. Maybe just shrink the collision region by a couple pixels to combat that? I dunno necessarily how you are going about your collision, but it could definitely use a touch of fine tuning.
-The contrast of the pure white/ pure black could get a bit disorienting if played for longer than several minutes. I'd suggest using a lighter gray in the background instead of the white to combat that.
But yeah, not a bad start! Keep it up.