Oh, didn't realise I can do this!
I gave it another try, because I wanted to see more of those "tricks" in level design. This time I made it to the end. I really liked the level with those radioactive balls that you have to avoid, that was quite clever. The two dark levels were fine, but I like my levels to be visible :D
All in all - a fun experience and thank you for taking time to respond with clarifications.