I remember playing this years ago and couldn't progress past the last few levels. Is there a cheat to skip levels or unlock them, I don't want to replay everything?

Nevermind... I just finished it.

The colors always bugged me, why does the color sometimes become black when I'm traveling towards it when it should become brighter? Perhaps because the game only simulates the frequency and we can only see a narrow spectra so it makes sense it is black on both ends.

Also the closing doors don't seem to work properly, or it is just my perception.