Played your game initially because I saw the screenshots and though, "That might need to be disqualiied because it breaks the rules." I was very impressed to see that you followed the resolution/colour rules perfectly! My map used the red/white/grey/black colour scheme though, and wasn't showing me elevation changes so I couldn't finish the last 3 levels.
Played it again after the jam so I could rate it though, and the map worked properly this time - looked just like your screenshot. Finished all of the levels this time and I think it's a great puzzle mechanic.
Although you are within the rules for graphics, and controls - you are likely to find people saying it isn't GameBoy-like. I'm sure you already know how your aesthetic isn't GameBoy-like. As for your controls, you do only use d-pad + 4 buttons, but the regular use of all four of those buttons doesn't match my experience of how a GameBoy game would utilise Start/Select.
Still, it is a good entry regardless :)
Edit: Thinking about it, I think that opening the map/menu is a completely normal use of either the Start or Select button, and it's really only the pick-up/place button that might be a little unusual.