Thank you for the feedback! Yes, I imagine it would be harder with a trackpad, but your suggestions are still valid. I did ponder on slowing down the bullets a few times, but I'm not sure if I'll go through with it yet as it may make zooming through the levels not as exciting, but I'll give it a go. I also thought of making the bullet freeze for longer in the air before rewinding giving more time for the player to react. Those are all things I'm going to experiment around, thanks for pointing them out :)
Glad you liked the music! It was a bit rushed and I will eventually rework them. Same for the sprites.
Yup, the background is very confusing at times, someone else has mentioned he fish bones as well. I'll do my best to blend them in.
Thanks for your helpful feedback! :D