Really cool! I'm a fan of both genres (noir + point and click adventure games) and you did a great job with the atmosphere and design. No Sierra online type unfair fail-states, just a nice, chilled treasure hunt. Loved it all the way to the end.
Can't think of much to improve upon, it was all very polished. The sudden cut-scene was slightly jarring, thought I'd been discovered!
Loved the dials for the audio settings. Great work. One other thing (as Columbo might say) - I actually loved the fact there was no HUD. Was very immersive. Maybe just an auto-hiding button or something in a discreet location on screen to bring up the Inventory.