Hi, this is a very interesting level but I had no idea what was going on. I got to an area, without cheating, where there was a red key and I could not get out
You'll have to manually kill yourself to get out (Ctrl+R), and look for the other key. That is what I did.
Apart from drwright, am I the only one who has this problem?
I've played through the level several times now, paying special attention to secrets and to exploring each and every path I could find, but I just can't figure out where to go from there - it's almost as if a powerup was missing or something (I have the climb and the highjump powerup). Other than that, I liked the level (up to that point, that is) - the atmosphere comes along very strongly, which is mainly because of your great choice of music!
I'd really like to continue with the level, if only I got a good (and maybe a little more concrete) hint...