i think you have the right idea for what makes a metroidvania, i like that you incorporated backtracking and even with very simple art you were able to convey what type of ability you needed to cross something. i think combat needs a lot more work, i found it very difficult to hit the pigs without dying. increasing the range and making the hitbox line up with the animation more would help a lot i think! it was actually kinda fun just dodging them though, they moved fast enough that it was nice jumping over.
if you improve combat you have the rest of the building blocks for a metroidvania though! :)