I was just reading elsewhere that OpenXcom made the game harder, for reasons such as all aliens with line of sight to the X-COM landing craft facing it so that they get overwatch immediately, and with the aliens having AI capable of being more sneaky, getting into cover, flanking you and using grenades more.
Are these comments more applicable to earlier versions of OpenXcom and not v1.0 or the nightly builds? Or do they still hold true? If true, are these AI changes toggleable via advanced options?
The reason I ask is because of the "gameplay is 99.9% vanilla" that SupSuper mentioned in the comments above. These kinds of AI changes would be more than a 0.1% change to gameplay.
I'm not sure if it's harder or easier or different; but I can say that the aliens don't always face the skyranger.
I was playing yesterday. There were a couple of times when I lost troops by simply taking one step out of the skyranger. But there was at least one time when I walked out, threw an eletroflare to spot enemies, and shot a snakeman in the back from inside the skyranger.
I've seen it mentioned in this thread that openxcom is an "approximation" to the original. I guess that's true in the sense that it doesn't mimic every detail. In particular, it doesn't mimic all of the bugs...
Even aside from openxcom; the original game itself must be emulated through dosbox, and slowed down and tweaked so that it will run in a playable way. So even without openxcom, the game is not quite as it would have been like when it was new.
As someone who has played UFO when it was new, and on newer computer through dosbox, and on openxcom - I can say that the only things that are noticeably different in openxcom are UI improvements. And I don't mean nicer looking graphics. Everything in openxcom looks and feels the same as the original; but some UI elements are improved. The biggest change is the option to show how many TUs you'll have left at the end of a move. That's an option which can effect playstyle and strategy, but I'd call that a positive change, and it's among the very few changes that anyone would ever notice.