The first half in Baldur's Gate is almost a guaranteed TPK with nothing but forced combat scenarios. It ultimately has nothing to do with the second half of the book in Avernus, which is a series of convoluted fetch quests. The only good thing about it was riding around Avernus in awesome vehicles in the second half, but even then that got boring after awhile.
The biggest problem is that the story is way too linear. Half of the time players choices don't even matter. The DM might as well just run nothing but combat like a video game.
Don't run this module without heavily altering it first.
