First I was pretty frustrated.
But after you figure out the right combination (or look one up in the comments) it starts to get really fun and addictive :D
Really cool game, great graphics and overall gameplay, but a few flaws:
No level-select
The last Modul was to long and a tad to easy, except for f and i...
Besides that I really enjoyed it, the ending was like "Mommy, I broke the universe!"