I want to start off by saying that I really like BGIII. I've enjoyed it immensely so far.
One claim I have seen made by a few people though is that it "doesn't feel like a Baldur's Gate game". I've kind of had that feeling a few times myself and I can't quite put my finger on why. One thing that has been running through my mind is the ruleset. I played AD&D 1st and 2nd Editions for years but I never played 3rd Edition or anything later. The rules in 5th edition really feel like a completely different game to me. As a game, I don't know enough to say whether 5th edition is better than 2nd. I can say though that it feels completely different. When playing BG3 it doesn't feel like the D&D that I know. This means that it feels more like a D:OS3 than BG3 at times.
None of that is a bad thing per se, but I just wonder how much the change in rules used is a factor in the "feel" issue that some people experience?
