Actually, this screenchot is self-explanatory.
I totally missed that hidden "*" in the mountains and kept on without the pogostick almost the whole game. This room with rocket boots could be beaten somehow, I thought. So, I came up with an idea to make something like 500 cloning potions, and... you see what happened next :)
Just tons of cloning and teleporting.
This took me something like 20-30 minutes... But after obtaining rocket boots I couldn't go on - these boots don't give ability to jump, they just level up the existing jump. So I had to spend an hour or so to find that pogo stick. Then, I needed another 10 mins to finish the game :)