This is pretty simple, and sadly I am getting glitches on collisions, and some coins are being generated in inaccessible places... The graphics are nice and bright, but the circles are distracting and quite unnecessary. I think this need a bit of work to make it into something enjoyable. If this is your first LD entry, do keep at it! Making games isn't easy.
Those circles in the background were a bit to much, and they make it very hard to see the player.
Also it is kind of easy bocouse the monset never jumps at you, so you could avoided him infinitely