I feel like there are a lot of challenging aspects to Syntorial. For example, sometimes a smearing effect is very difficult to tell if it’s coming from detune, unison, pulsating volume mod, or chorus. These are fairly difficult to get right in each patch.
The main problem I’m having, however, is with oscillator sync, ring mod, and FM. After finishing those “units” I scored pretty well, but once you get to the later challenges with all of the above possibilities it becomes quit difficult to figure out what is what.