After you do the major easter egg, you get a wunderwaffe power up right? Yes. After that every time you get the death machine power up, it's a wunderwaffe! Just thought I would share that knowledge with you!
There is an Easter Egg, similar to the one in Ascension that if you complete the riddle, you get a death machine, but in COTD, its a Wonder Waffe instead of a Death Machine.
(If you don't know that, you have been missing out)