Hi, The Gacko!
Thank you so much for playing my game and taking the time to write a so detailed feedback. I'm really glad that my game caught your attention to the point you take the effort to write this review.
Thanks for all your suggestions. Indeed, I'm not happy with the green dive bombing alien too. I liked the idea of the arrow indicating it is coming. Definitely, it got a place on my to-do list after the end of the game jam. I'm going to have a look for bugs on the green beam shooting aliens as well.
In my earlier version of the game, the bonus was enabled straight away, but I felt that it lacks a strategy to use it, so I implemented the x button to use the bonus. The text tutorial in the first level is a good idea and it got its place on my to-do list as well.
Thank you for sharing your thoughts on this!
I'm looking forward to playing your game! I'm sure you will bring a great boss for your game.