Hi guys, what exactly is Punch? A compressor / limiter / filter???

From the official TE OP-1 guide: hard hitting low pass filter

is there anything that represents compression?

Yes, the master compressor (MIXER mode, page 4)

Punch(green) seems to make the level meter move in the effect,which suggests gain reduction or transient ness.
Orange is mix between dry and effect.Freq is for filter.while white(rounds) is resonance and filter slope.

IMO Green is resonance and White is slope. If you crank Green and sweep Blue you can hear it pretty clearly -- sadly it's sort of weird and gnarly and ends up mostly making crackling/distortion sounds at higher values.

I think Punch is just a low-pass filter, but it still "compresses" in that you will get louder bass for a given volume level (i.e you're removing highs to make room for more lows.. AFAIK, I'm not an audio pro).

It definitely seems to work synergistically with the Drive section, in that low-end seems to trigger the compressor more than highs, so running something through Punch (which makes the signal low-heavy) will result in something that moves the compressor more than it would without Punch.

Nice to get 2nd opinion .
Yes Punch effects Rez too,in combo with rounds.
80+ punch with 20 odd rounds will self oscillate .

I also here some bit reduction sometimes…?Not sure how punch interacts here.