In the Compressionist game, you are trying to match the sound you are creating with the available knobs to the sound you are hearing. What I do is adjust the volume first to match volume of what I'm hearing, then adjust the attack speed (if that's the only knob available). Since attack speed is when the compressor kicks in on each beat, the longer the attack speed, the louder or punchier the beat is because it is letting a lot of the transient through before the compressor clamps down. The shorter the attack speed, the more distant or less punchy the beat is because less of the transient is getting through before the compressor clamps down. It can be hard to detect the difference at first but keep plugging away at it and it will become more obvious. The Dr. Compressor game is the one where you have to determine which is more compressed. In the earliest levels, they are using the attack speed (faster is more compressed), but in later levels they also introduce ratio (higher is more compressed) and release speed (slower is more compressed). For higher ratio, listen to the level of the background noise coming up. For slower release time, listen for the smoothness of the compression effect.