This version uses a different input buffer, which more closely resembles the input of the Crash Sync. Though it has a greater gain. I found this gave more sustain. The Ugly Face has a gain of about 200. The Revolting Visage uses a gain of about 1000.
I took the envelope from the Ugly Face which is simple and elegant and seems to work well for this design.
I also borrowed the Threshold from the Ugly Face. Which allows for self Oscillation.
These last two features do not exist on the Crash Sync. But, are a lot of fun to play with.
I changed the output to be directly taken from pin 3 of the 7555. The Ugly Face used a strange arrangement that was also connected to pin 7. The pin 3 arrangement makes more sense to me and is simpler.