Unknown 64 pro is a one oscillator synth.
With 4 waveforms triangle/pulse/saw and noise
A filter envelope with 3 filter types lowpass/bandpass and hipass
A pitch envelope /pulsewitdh envelope and volume envelope
Every Envelope can be inverted and has 13 different curves
A ringmodulation oscillator or a ringmodulation BPM LFO
A BPM LFO for the Pulsewidth/cutoff/and oscillator pitch
3 big sequencers for creating the real c64 arps and percusions
one is used for the octave and notes
one only for octaves
one for the waveforms
All 3 sequencers are BPM sync with speeds from 1/16 to 1/128
They can be ended at every step or looped
also a vibrao/bitcrusher/midilearn and panner
Envelope restart/pickup
and ofcouse 128 presets !!!!!
:P

Unknown 64 Pro is DonationWare you must donate to get the full version. The free version thought is fairly functional, you can run through all of the presets, you just can't tweak any settings yourself.

http://odosynths.com/
http://odosynths.com/unknown%2064%20pro.rar