I absolutely love Devil Daggers so I was excited to try this one! The gameplay is definitely solid, the powerups were a great addition to it I would highly recommend giving that part of the game extra time. I don't think the map was too small, but I was having trouble staying on it because of the lack of audio/visual feedback I think. Maybe add some footstep sounds, and have a different floor material on the edges so it makes a slightly different sound while walking there. I also wished the jump had a little more 'oomph', I was having trouble even telling if I was jumping most of the time. I also had the 'quit' bug when I fell off the map, it would bring me to a black room with a single enemy spawner in it, I had to just hit X on the window to close it.
As others have said you the visuals have a really good style, keep building and polishing that and you will have a really great looking game on your hands! Audio would also be a huge help, even just some basic placeholder stuff would help with getting feedback. I hope you keep working on it, with a bit more polish this could be an awesome game!
Also I appreciated how detailed your dev log was, I need to up my game on specific patch notes!