Well i liked it a lot and very good as a first game, here was good sprites and so on but just a couple of improvements:
If you hold down the jump button and continually jump, I've noticed that you jump to a lesser height than if you just press the button once, which is annoying if you're trying to clear multiple platforms quickly.
also, maybe implement a particle effect when you land?
anyway, great platormer
i like it, simple but have a good desing
Simply awesome !!! seems like Rob is our next Mario...