Funny. It needs some balancing with the volumes, though. The first test is simple enough.
The tones in the second test are way too quiet in relation to the voice. So I crank it up and it has some bad sound artifacts and the voice is too loud. Also, it's not really clear when a sound is front or rear. I got past mostly through guesswork.
Then the third test... There really is no point to pressing three keys instead of one. It's ok for flavor, I guess but an unnecessary complication in a test that's already hard to parse. I never heard the gas sound so I played mostly by looking at the time.
All in all, a fun little minigame with great humor that can be very easily polished by adjusting sound levels.