This is a pretty cool idea! My main criticisms are the bullet sound (which forced me to turn the game volume down because it was so unbearable) and the fact that losing to the final boss is so devastating. It took me at least 5 minutes to get to the final boss, just to be instantly killed and sent back to the beginning. Additionally, as others have said, the F4TE would be impossible to beat without exploiting a glitch. That being said, I still had a fun time killing all the enemy types and getting 1500 points :)