I like a lot of things in this game. The graphics is nice, the UI clean, it's easy to know what to do and the sound is OK (which is non-trivial achievement, given the limitations) and the theme is very strong in it.
Sadly, the game just isn't fun for me. The game play is just too simple (I mean, not that I can last too long at higher speeds, but that's not engaging me in an enjoyable way) and I kinda hate a mindless grind in video games. I am convinced you achieved what you wanted: it's just I hate it.
At least, it's a stark reminder why not to get a job at manual assembly line.