"Our biggest challenge, hands-down, was getting the data-streaming working, to allow us to have a seamless, interconnected world with no load events. I think we were one of the first developers to tackle this problem (along with Naughty Dog, on Crash Bandicoot). It proved to be way more difficult than we had initially anticipated – if I recall, we were still struggling to get the textures to dynamically pack correctly, just a couple months before release. We ultimately got it working by the skin of our teeth, but I wonder if we would've embarked on such an ambitious plan if we'd known how difficult it was going to be! Our second challenge, of course, was figuring out how to store two sets of data for the spectral and material realms, and how to implement the real-time morph between the two environments. Our initial plan was over-ambitious, involving texture-morphing as well as geometry-morphing, but we realized pretty early on that our texture memory (and time) was too limited to achieve this. We came up with the idea of leveraging the 3DS Max animation timeline to attach spectral values to the vertices in the geometry – i.e., frame 0 was the material world, and frame 1 was the spectral realm (or vice versa; I can't remember for sure). This way we could alter the x,y,z coordinates of each vertex, as well as its RGB lighting values, to create a twisted, more eerily lit version of the physical realm. Our ultimate challenge, though, was schedule and scope. Conceived as an open-world, Zelda-esque 3D adventure game, Soul Reaver was incredibly ambitious. Crystal Dynamics’ Gex engine gave us a leg-up on the 3D technology, but in essence we were writing a game engine from scratch, while developing a new IP. These days, a developer wouldn't think of attempting such a thing in less than three years (minimum), but Eidos wanted the game in less than two. In the end, we shipped Soul Reaver in under 2.5 years, but not without some unfortunate eleventh-hour cuts which still pain me today. The scope of the game was definitely too ambitious, but if we had shipped the game that Fall, instead of that Summer, I think we could have reduced the scope of the game more elegantly."