The upcoming D3 version (from the BFG edition) is the "original" PC version of DooM ]I[. It never came out for the 360 before. The original Xbox version had major changes and/or enhancement of the levels and their overall design, many of them were removed, other are split up versions of the original levels because the hardware limitation of the original Xbox. Also the engine is not exactly the same, its a toned down version. In its core is different and this explains why the upcoming BFG version is not featuring coop for the 360 - they are not porting over the original xbox version but the PC (the true) version which never featured coop. I doubt they really redone all the textures in HD, maybe for the new levels but for the original levels I bet they just used upscale and called it HD. If you played just the Xbox version of D3, you should try either the PC version or the new BFG edition for the consoles. You will see the differences between the original Xbox version and the true version at least + you will have the benefit of the new features such as the checkpoint system, a reserved duck tape from the latest delivery and ofc the new levels. When I played the game for first time all the duck tape was already used so I was not able to attach a flashlight to my weapons, which sucked big time.