GFS:K is a nice little mini-metroid clone. The art is really quite nice, pleasing colors, great detail, some nice animations. The game is incredibly easy as none of the enemies move much, I didn't get hit at all, even by the boss. There's also just not much too it, but I understand the limitations of a game jam's timeframe.
I think it could be the bones of a creative Metroidvania, so I hope the developer keeps at it!