Some of them are the same ( in the first and last Boss Stages). Here you can see the sketches and the final 3D models, also see them in some gameplay.
Whit no more to say, I'll let the images speak for them self.
After my first sketches, went to Blender to start modelling them.
Hope you like them as much as I do, I've tried to make it Lowpoly style and I think I've managed to do that!
See you soon!