An incremental game.
There are random people (or just “sources of sound/audio”) on your map, talking, murmering, etcetera.
All you can do is move a microphone around.
If you catch juicy gossip or important info or state secrets or whatever, you score more points.
If people notice your mic, they’ll move away, or they’ll destroy it and this round ends, etcetera.
If we go a little more for that “SPY” theme, then we have some more options for upgrades and thematic mechanics. Alternatively, we might really lean into the SOUND thing and do actual interesting audio/sound/positional audio/microphone stuff.