Aora

Good start for demo! though I have to say that you need to at least be consistent with controls. In menu, keypad is used to move options but in game A & D is used to move instead
Also I knew that I can kill the boss by stomping it AFTER I'm stuck not knowing what to do for couple seconds.
If you want to make your game better, spend some time putting instruction in readme.txt and in description above. And put correct information in game too, instead of "beware of Grogs", say "Grogs are deadly, jump on them to kill them"
Also, avoid putting enemies close to starting spot of a level. Always give safe spot at start of a level

The graphics are good and enemies are convincing OTOH :)
Well, if you can do what I suggested above, this can be good game :)

Wow! I like this game!