The real
technical achievement that was
UltraHLE was the
HLE part, or
high level emulation. The N64 was very hard to break via
brute force, which was
project unreality's approach. The N64 was
programmed in C, which meant a C
compiler, and tons of recurring code. Noticing this, the authors of UltraHLE basically
emulated the
toolkit of the
N64, based on the
opcode patterns. Thus the concept of High Level Emulation, or emulation of code patterns. Thus there are compatability concerns with this approach (ones that didn't use the development toolkit won't work), but games that do typically work well.
It's an interesting approach, and a brialliant observation by the two esteemed
authors. There have been
teases of an update to this amazing
program, but nothing has materialized. I don't blame either
RealityMan or
Epsilon for leaving the scene, they didn't deserve the crap that they got.