Digging into the keys with aftertouch brings in a bit of a growl, and a dedicated control fades in an octave doubled sound.
If you want to get more radical, grab the mod-wheel and the whole thing gets pumped through a cranked-up amp for distorted leads to make your guitar player weep.
A convolution reverb, plate of course - how else are you going to record your Mellotron? rounds it all out.
Optimized for real-time playing. The demo is played in real-time. Uses after-touch (key-pressure), the mod-wheel (distortion), and two midi-CC's with dedicated knobs in the custom Kontakt script.