I found Nitro's Knuckles wad to be crappy, for these reasons:
He doesn't have good shading,
His walking frames' head bobbed too much only on the front and back, otherwise he forgot to do the same for the rest of the directions,
His walking frame hands are too small and were edited from Sonic's,
His falling frames were partially edited from CZ64's Mecha Knux,
His running frame hands are too small,
The rest of his running frames don't look right - His dreadlocks don't move, his legs and feet don't move in the right way, still retaining the walking frame look, and Knux should also be leaning more forward than this for running frames,
His spin/jump sprites seem to be incomplete, and not placed correctly for the actual animation bit (For example, the diagonal back sprites look odd when you see them in-game),
(Other places where the hands are too small) - The spring up frames, the back and diagonal-back of the falling frames, the back of the gliding frames and the back of the climbing frames,
The original Knuckles sprites are not as good as they originally were, thanks to the colors changed on them, compared to the Knux.plr that comes with SRB2,
And Overall, this wad is DEFINATELY NOT GOOD! (There could be other things that are bad in the wad, but I can't list all of them!)
That's why I once set out to make a much better Knux wad, long before Mighty was started, even though it was several years before I actually joined this January. It didn't look that good, and all I had was a complete front walking animation, partial bits for other directions and a slightly crappy, but complete gliding animation. I gave up on it, and I have produced much better sprites than then ,such as the Knux walking sprite I recently made.