Enjoyment 3.5/5 - Decent enough to moving around to collect flies but still nothing too special. Snakes are fun though with their movement.
Concept 3/5 - Very basic arcade style idea without too much to spice it up. Could have used an extra mechanic or two for it to really stand out.
Presentation 4/5 - Decently nice pixel art! Very polished menus and overall very nice looking.
Use of Limitation 1/5 - As you said yourself, it was going to be added but can't judge what isn't implemented.
Overall, a decent start for a game though missing the limitation and needing a bit more design.