Fun short game if you don't mind hand cramps and carpal tunnel.
I do like the Gameboy style of it and the colors and graphics are very fitting for it. I also live the music, although it reminds me more of C64. Then again, that is just me.
I kinda agree with some that I wish it were longer, but I'm glad it isn't because of the controls. Shooting and changing directions of shooting is fine, but the movements needs to be smoother. Having to press one square at a time is tiring on the hand and I would hate to think of doing it were it a full game.
It would have great potential as a stand-alone if the walking control was fixed and if it were longer. May be something to consider in the future. Still glad I played it.