Looks like it actually implements quite a few opcodes from Csound. A quick glance makes it seem well suited toward quick integration in existing projects, with a very small footprint and codebase. Could be good for experimentation or learning low level DSP programming.
For realtime multi-voice synthesis, I keep using a not very well advertised side-project that performs reasonably well and also doesn't have a huge codebase: http://pippin.gimp.org/lyd/
