I downloaded this game and have been playing for around half an hour now, and I feel I've done everything there is to do. I'm aware it's a simulator and there's not meant to be endless fun content, but I expected a little more.
My main issue encompasses two in one. Firstly, there's no proper instruction as to what the different meters mean. The player can assume what each of them mean, but I still have no idea what the second meter means. There have been times I've taken longer to complete a shave and been awarded a higher score for that meter, and there have been times I've tested a super quick shave and gotten a low score.
Secondly, if it IS a speed meter, I feel that it puts far too much pressure on the player to rush shaves. This is a simulator, and it's a short game. You need to allow players to get as much out of the game as they can. Encouraging players to "complete" the game as quickly as possible only goes against you as a developer.
My advice would be to get rid of the grading altogether. Keep the immersion, and have the customer leave a tip based on back-end performance checks. One of the biggest draws of this game for me is the feel of the place, and having a big score sheet at the end of every shave just breaks that feeling for me.
With all the above being said, this has fantastic potential. Tweak/remove the "speed" meter, increase immersion, and really push the 40's/50's American aesthetic.