The paid version has a gallery and additional animations at the end of the saihata's health level. And in 0.79 the territorial paid version went to the front, there is a swamp.
I originally did free, but ended up buying it because it ended up becoming my favorite, and agood game, want them to continue to work on it, having the $$$$ hopefully persuades them to keep up the great work. Would recommend myself if you have the spare money.