Chill and fun indeed, I like your art a lot! Nice buildings and good job differentiating things in a 1-bit palette. Fun fact, you can pre-fire down the map, with your bullets going and hitting things you haven't seen yet, which makes the game very easy.
Also sometimes when moving back up to the top row you get stuck on a tiny bit of collision, which isn't gamebreaking but is a bit annoying.
Long live Biscuit and curse those bloody geese!