There are a few different endings, you probably saw the end sequence of what happened to the various characters after the game - your decisions affect much of that. And of course you can get three different variations of the end, depending on what you do at the very end.
We will be giving away Steam keys to everyone who purchased through our own site. Unfortunately we cannot do that for GOG purchases, but keep your eyes open within the coming week or two for good deals on Driftmoon.
As for the ability scores, from my point of view, I've tried to make it impossible to have an optimal system, and to provide variety. Getting a lot of levels by getting max intelligence does net you nice bonuses from the talents, and you can easily use that strategy on the easier difficulty levels - but on any of the higher levels you'll need to those fighting stats as well.