The teleport window is kind of hard to balance, since some players struggle to do it and some do it on accident, so I will have to come up with an idea to fix it in the future.
Changing the fire button is a very good idea since I have many times accidentally clicked the main menu or the restart button in the game over screen after I died, so thank you for reminding me to change that!
Thank you for the compliment regarding the sprites! I also saw that the background lacks action during playtesting, though I just didn't have the time to change it. The same goes for the ship animations and others.
I also considered adding more enemies and a boss, but as I said, I was tight on time. After the rating period is over, I will come back and do my best to add more features to make the game more fun!
Thank you very much for sharing your thoughts, I am glad you enjoyed it :D