Hello, Plide; and thanks for playing our game!
The last color is supposed to be white-ish really - You mix Red Green and Blue to get it - but the color seems to be bugged as well... The door opens with the correct potion/potion mix, however, so the game should be finishable...
Regarding the tutorial, we'll be adding one as soon as possible. Can you please tell how did you ended up getting stuck on these points? i.e. what were you trying to do, and couldn't figure out? And lastly, which part are you referring to, when you say the "first crawlspace"?
The assets are a little big, and not the most cleanest ones for a level edit, I agree... We will address these & the above bugs for sure.
Thanks for your feedback!