Overall a really fun experience.
The map which marked the coloured doors really helped with exploration and the game is surprisingly large.
I had a few little gripes with the controls, but these are more personal nit-picks than anything major.
-Jumping is a little too quick/heavy for my tastes.
-Crouching felt a bit clunky and often led to me getting hit. For example: moving then shooting whilst trying to crouch at the same time would leave you standing even when still holding the crouch button after. Personally I'd rather it if you only stayed crouched whilst holding the button and not on a toggle but that's me.
But otherwise a very solid entry. Whilst not doing anything particularly new it really nailed the raw 'metroidvania' formula we all know and love.