This is really the perfect setup. Incredible art, jaw-dropping effects, convincing narrative and voice acting, intelligent puzzles, friendly UI ...
So, then, why am I giving it 2 stars?
About halfway through the game, things start changing. First, you become a comic book action - thing - wandering through repetitive tunnel structures, and then it goes downhill. The story starts turning cheesy, the clues alternate between directions and misdirections, more than riddles they are either very direct or just ambiguous meaning it turns into pixel hunting.
I don't want to spoil too much, but when it touches history all of the great world-building completely falls apart. It's not dumb fun in a campy sort of way, more like dreary and unimaginative. The great voice acting completely falls as well and that is when pixel hunting ramps up. Walking becomes buggy, the story makes little attempt at making any sense of this. In short, it becomes a chore, and when I'm working I ask for pay, rather than purchasing.
It's regretful because the setup could be for one of the greatest games ever created and it seems to others that is the case. If you know a little bit of history you may find the hamfisted approach not worth the absolute lack of beta testing that section implies. Honestly, I didn't finish it, I moved on to better things such as Planescape Torment. It's up to you, it's your time and your money. Maybe if you temper your expectations you'll enjoy I sadly was very pampered with the incredible setup so that felt like a shower in battery acid. Not painful at first but it was burning before I dropped this (PS wear gloves, battery acid has a delayed discomfort)
PS Bought this at Waldo's 1 dollar mart, and I can't think of a more fitting place for it. It's a shame really, it had so much potential.