The loop is compressed at a fixed 6:1 ratio and -20 dB threshold, and you judge either the attack or the release time. These two settings decide whether compression keeps the punch, kills it, or makes the track breathe.
Level 1 compares a very fast attack (1 ms) with a slow one (35 ms), where the difference in punch is obvious. Higher levels bring in the in-between settings and, at the top, ask you to separate neighbors like medium-fast and medium. Release questions follow the same path, from 50 ms against 700 ms to much closer pairs.
Punchier. The compressor waits a few milliseconds before reacting, so the start of each hit gets through untouched. A very fast attack flattens that initial snap and makes drums sound softer and further away.
Listen to what happens right after a loud hit. A fast release lets the level jump back up quickly, which can sound like pumping; a slow release keeps the level down longer and sounds smoother, sometimes flatter.