The Wii version is $39.99. The DS version is $29.99.
I have picked up the DS version, and I love this game. The price point was probably too high for many, but the extra content is worth it. The two versions for the Nintendo platforms contain so much more than the $8 download of Retro Evolved on the 360. There are 64 different levels, background/atmospheric effects that change gameplay, and tons of new enemy types, plus a customizable sidekick. Owning both the DS and Wii versions allows you to open a bonus unlockable galaxy at the end of the DS version of the game too.
The DS graphics are neutered and it does suffer some crawl when there is a lot of action going on, but I have not regretted paying $30 for it, it's that good. I have not played the Wii version yet.
