Unreal Windows game

At one point in developement Unreal 2 was called Unreal: Episode II even. But that's all "forgotten history".

Plus there are also Unreal games you probably don't even know are Unreal games. Devastation and Gears of War for example. They basically (still) take place in the Unreal canon universe, no matter how silly this statement might be. Didn't you notice the COG logos in UT2004? That's because that game reused content from Unreal Warfare which was being restarted in developement at that time and evolved into Gears of War. Devastation was something that started as an addon, evolved into Unreal: Devastation as some sort of a prequel game to the Unreal series, but after cancellation and search for new publishers the game was remade on the new Unreal Warfare engine into simply Devastation with much of the ties removed, except for few references for a keen eye like Liandri Mining Corporation and their defacto start in that game. Yes, it's true. It's only referred in a single level of the game and you might miss it. But you will also notice that several of the more scifi looking weapons(or even the bolta harpoon gun) are more Unreal in design and that's because they came from the earlier phases of developement.
In a funny way that game is more Unreal like in terms of exploration and progress than Unreal 2 was. And nothing's quite static there either, even though it does show how broken the unreal warfare physics often were really. Since why the main games never truly bothered to utilize it and with pariah DE chose to utilize Havok instead. Pariah might even be originally related to some Unreal project too given that it was started around 2002. maybe as singleplayer component for Unreal Warfare/expansion pack? This last bit is not confirmed but only because the developement of pariah was so tight lipped. The "Shroud" however are basically exactly same as the Geist once were in Unreal Warfare. Basically techno based Necris as opposed to Gothic etc.

Its really sad, especially if, like me, you know of the many cancelled games and expansion packs that would have featured singleplayer content.

Unreal 2 had a troubled developement cycle and not everything can be blamed to Legend staff (in fact very little when it comes down to it). It was kind of like with Blood 2 except they got a chance to more or less polish Unreal 2 so it wouldn't be a buggy mess, has to do with the talent of the coders of course. In fact to use your own word, it was gutted and shuffled around, the game starts with m08 maps which is mission 8 for crying out loud. Mission 7 was cut altogether and only little tidbits remained in the game and the shian models replaced with black cubes...
the 2000 alpha version had two draft levels for mission 7 and sadly it's all we got now. It was to be featured in an expansion that never came to be either.

And still it can't really be counted as a sequel, it never really was, more like another "chapter" but not playing as the Unreal hero. It drifted away from Unreal more and more as developement went on (and then last minute references were tacked on). Initially the concepts for some maps like the drakk homeworld were taken from unused ideas from original Unreal.
There was a plan for a different Unreal 2 game very early on in 1997 but that was to be a direct sequel. The Unreal 2 that started in 1999 was meant as another step in the series but having slightly different direction. However the focus was originally more on dynamic situations, while the released game is very very static.

Agreed! I dream about that too.

Can concur. I've been pining for something at least emulating the style of OG Unreal for years, but alas, it seems it's a pipe dream. Shame as well because Unreal is one of my all-time favorite games, and it deserves more love than it gets.