There are actually many many differences between Nuendo 1.61 and Nuendo 2.2 if I remember right. First, the routing is way more complicated, but incredibly powerful. Also, it allows you to monitor or record the same input to different tracks at the same time which is handy if you want to inout monitor just certain effects on an input and not the whole inout signal (latency issues etc....) The routing is more complicated at first, but once you get used to it its FAR more powerful and flexible. Also, I believe with Nuendo 2 there was an udpated ASIO core, a reworked audio engine, the FX channel options as mentioned above, a phase reverse button added to each channel strip (FINALLY!, now if next time they add a 360 degree variable phase shift I will be really stoked), a more complete input mixer, more surround options, better mixer screen options and more mixer screens (larger meters, more variable etc...), a pre and post insert section on the master and groups, and probably more codecs and video options that I am not aware of because I don't use them. Also, for me its more stable.