I beat level 18 tonight! And here I was thinking that I maybe would have to give up after the last time I tried the level for the first time. At the end almost all the red and blue blobs were following Aldo, but he narrowly reached princess Ruby. Whereupon Ruby instantly transported herself to another place where she caught herself stuck again, namely level 19!
O no! Luckily, Aldo comes to the rescue again. After too many tries I managed to gather all the diamonds, but he didn’t succeed in flipping the right switches to open the door that bars the entree to the princess and get there unharmed. Why aren’t there any of those magnificent swords lying around?
After this I played some Shadow Switcher. I reached level 5 before dying. I downloaded the Cracked Version released by Laxity, just to be able to skip the levels I already completed by pressing C= or begin with the level I last played directly from the menu. I seem to understand that you can also skip levels in the original version. But another added feature of the cracked version is the intro which has some nice music.