Yep, it's for unlimited/unrestricted play ... so in this case it's a trial. But a community has in fact grown around this game, and in the future they could enhance it for additional IAP funds, sort of like the dagobah IAP in angry birds starwars. I don't know if they're actually planning to do this particular thing, but he even says that he wants his games to be ongoing services that evolve and improve over time.