Nightmare is now suitably difficult - completed but tough. Technique: buy a 18-yellow sunstone and immediately scramble it and hope for somethign that doesnt suck (I got the 0-cost meteorite) ... then just try to survive until you get a yellow cube ... then cross your fingers for a cave painting. With the cave painting you can upgrade the cube every turn, and eventually it gets big enough (100 or so) that you can actually win the final level.
