Well a demo is always nice, so you can see what you really get for you money. Lite versions often include one track/course, so in a sense it's a demo.

Or you can do like Vodafone did a long time ago, limit playtime to a half hour or something like that.. But then you could play through the whole game so that's not all to good.

I don't really know how you're do right now as the game crashes right before it should start on my N900(I see a picture for like 0.2 seconds, then it crashes).