A is the easiest.
A# is a bit harder because that is where the obstacles come in.
B is harder because of the leaky pipes.
C is a tiny bit easier than B...but the red DEFINITELY makes it harder.
C# is harder...but
D is MUCH harder than you think. D3 has only red obstacles!
D# is where the yellows and double exit pipes start coming in.
E is very tough.
F is even tougher!
F# is so hard because that's where the red pipes and drops start coming in.
G is SO-O-O-O tough you might want to STOP!
But that doesn't stop me there! G# is hardest. These levels might make you say, "Forget it...I'm quitting!" I could not figure out how to complete G#2! I rage quit...but after a while, I said, "I know I can do this." So I persevered and completed G#2. But that's not all...G#3 was SO-O-O-O-O-O-O-O-O hard! But I persevered...and completed the game!
 "Accelerator"){kind=icon}
 "Drop."){kind=icon}