I like metroidvanias and overall your game was pretty clever and fun to play, there is sopme things i want to point out but remember that i liked your game and this is just feedback for future:
-watch videos about good platformer controls becouse character felt kinda bad to control sometimes, especially with jump mode
-making some textures change in different part of world woudve been nice becouse now everything looked realy much same
-gun is op and shooting is just boring obsticle
-collectables were awesome and well hidden, found them all. Nice work with them