I've mentioned BG 2 because many people insisted on a yardstick to measure Lionheart against.

I'll answer your question while also answering the question about multiple endings.

There are choices that you make at the beginning of the game and throughout that could possibly affect the ending encounter. Without giving away any spoilers, the ending encounter is the same antagonist, but it can play out very differently depending on how you made these choices early on and later in the game. There is no wrong choice, so you don't find out at the end that you made a *bad* decision early on, they'll all be viable.