Smitty over at TRI sends along a fix for Voodoo 2 & 3 users for the second Nocturne demo (53 KB). Here's the poop on this from Nocturne Lead Programmer and Co-Designer Mark Randel:

For Voodoo2 and Voodoo3 users
Only to be used for Nocturne Demo #2

"DirectX is a very complicated API. Nocturne uses a blit function in the DirectX API that 3Dfx does not implement yet in their D3D drivers. Other 3D games do not use real-time shadows, and do not exercise some of the DirectX functions that we use in Nocturne.

This TRIDX6.DLL contains code to emulate this blit function using the main CPU instead of the Voodoo card. Because of this software emulation, Nocturne will not run at an optimal frame rate, because normally Nocturne can do other work (like cloth simulation) while the hardware takes care of this blit.

Please remember that Voodoo cards can only render in 16-bit mode. Nocturne is optimized for 32-bit mode, so you'll have to decide whether you like 16-bit hardware, or 32-bit software mode best.

Due to the software memory blit function, please only run 640x480x16bpp with this video driver for the moment. Any other resolution will probably crash immediately. Usage of this video driver is governed by the software license agreement that you agreed to when installing the original product.

3Dfx is scheduled to release their next Voodoo3 update on October 15th. This update contains the blit function that Nocturne uses, and Nocturne will run at full speed with this new driver. When you download this driver, please delete this TRIDX6.DLL and use the original one that we ship with the game."