You hit the nail on the head with all of your feedback! We've very slowly been developing the game further for a small improved release after the jam. All the things you've listed have either been addressed already or are on our to do list!
In the new development build (not published) we have fixed your targeting issues, and improved the tutorial messages, improved the controls in general, improved performance, and made the whole user experience a little clearer. Other things that are coming is enemy artwork (with animations), more UI improvements, better balance and wave design, an endless mode, and many more sounds and music
Thank you for taking the time for such a detailed write up! And thank you for enjoying the game!!