Needs work.
While this demo will definitely be blammed, you might have something here. I'd recommend putting some more time into making the motions fluid, and when you lose, you should start at the level you were on, not the title screen. Also, the music was pretty annoying, and your character and the grass don't fit in with the whole laser, slime monster thing, and those two together are pushing it as it is. But work put into making it isn't a lost cause, if you want to take the effort.