I found the red key. I really liked this level. The look of it is, sorry to say, somewhat drab but finding the powerups and the keys was just puzzly enough that when I did find them it was with audible "ahahs!"
found two different endings and everything else including the 4 keys except for the umbrella. Is the brelly in this level? I liked the use of those gray tunnels that overlapped other areas and having to find out to use them.
Short and sweet, but good game play. Fine work.
The red one? Sure.
First, go up to the room with the pipe machine. Jump up and grab the ledge next to the pipe at the top. Follow the hidden passage, go up, and get the eye. Then go into the black cavern on the left, and go into the hidden passage revealed. Then, in the cave, go into the pipe, and get the red key. :D
Didn't notice that SGE. Thanks!