Some interesting things, but definitely buggy.
I had the UI just glitch out multiple times.
The last two? bosses basically require you to use a specific bomb.
The game tells you to click on the screen. Doesn't tell you that you have to click on one side or another. Needs a dividing barrier and a confirmation option. Also, give us a save menu before the selection so we can go back and select the other option.
The keyboard controlled option honestly felt like the weaker option, but the mouse controlled option is sort of buggy. The ship doesn't automatically connect to the mouse and if you move the mouse off the window, the ship stops tracking completely. This can be extremely frustrating.
For the mouse controls, instead of having a loose mouse, you could instead have it so that the game pauses with instructions until you connect the ship with the mouse. Or autoconnect it and have it at the mouse position from the start. Also, when using mouse controls, you want the mouse to be captured in the window during fights at least so that the player doesn't end up clicking outside the screen and end up switching windows mid-fight.
Projectiles honestly move a bit too fast for this sort of game. With danmaku games, there are enough bullets and usually some clear indicator of where the bullets will come from (either the boss or some obvious guns). Here, it wasn't so clear and the bullets were sometimes offset. This makes hits feel cheap sometimes.
Blitz does not work completely correctly as it only lasts 15 frames (1/4th of a second), but it has a slight delay before it activates. That means you can trigger it, get hit, then the animation displays and it activates.
Try to avoid same color projectiles as the background. Green on Green, Green on Red, Red on Red, Red on Green. These are some bad projectile colors. What would be better would be multiple colors or a different color outline. This makes projectiles visible so that it doesn't feel cheap when you miss or get hit. For the final boss, instead of solid circles that may be invisible to colorblind people, add in an outline, some shading/coloration, and maybe have each circle be three colors that spin instead of one.
Add a replay option to get a higher score for the missing bonus points.
Show us what enemy we would fight when we select an area. Think of how Rockman does it with showing you the enemy itself instead of the area.
You have two invisible planets.
HP indicator would be nice. See Touhou.
Honestly, some of the controls are pretty bad. You have to press a button that isn't in a good position to activate some effect. UI for example. Not close to ZXC or the arrow keys or WASD.
While Rockman makes it so that each boss has a special or two that kind of counters them, in general, you want all specials to be viable unless you are going to show us what enemy we are fighting so we can better know what to expect (which is sort of how Rockman handles it).