This game is very charming. It's gotta a lot of style that fits really well together. The little loading/intro scenes with the wave in the background is especially cool.
The concept of rolling a slot machine to be able to choose between a couple of different bosses was pretty interesting, as well as the power up tombola. Although I did find myself getting frustrated if I only got one power up option, so I'm glad that there was a reroll.
The bosses were fun and even more fun once I had a little bit of speed. Although I do wish that they had more attack patterns than just two different types of projectiles. The final boss twist was neat, I'm glad that it had a little bit personality/story thrown into it.
Great work!