Does the website demo work on an iPhone (I don't have one to test)?
The standard solution is to give away a bunch of levels for free and charge for additional levels using IAPs.
Relying on the App Store is a good strategy for development firms that cannot build their own hype. So far, I'm guessing these guys are doing an okay job.
But I have zero data on any of this, hopefully they do and are acting appropriately.
[1]: http://www.addictinggames.com/puzzle-games/3dlogic2.jsp
Free sells.
This one has much better controls on the web app, as well.
* An iPad version is needed. The graphics seem to be high res enough to make an iPad version feasible, and if this is on the iPad I'd buy it for sure. I don't really like the idea of trying to trace out the paths on the tiny iPhone screen.
* Charge money for it. I'd definitely be willing to pay personally.
If I had an iDevice I would pay for this. Good luck.
I'm not sure how making a game for free is a business, but still, best of luck!