The factory should really rethink their production strategy, this is producing too much waste! Jokes aside, This is quite an interesting little game! The whole idea is super simple but somehow being quite fun. The Daruma Dolls are very cute, and I am not too willing to break so many of them, but hey that's what the job says.
For some suggestions, I'd sat the belt moves too quickly, and it really doesn't leave much time for the player to properly check against the requirement, especially when the game decides to suddenly change that, and we have to re-learn the newer pattern. If you ask me, I'd probably lower the initial speed quite a lot, just to ease the player a bit during the early game. This leads to my second point, which is to add a failure state. It's funny cause theoretically, you can just never lose if you never do anything, which sort of defeats the whole purpose gameplay-wise and story-wise. I would probably change it in a way such that you have a limited number of lives, and each time a wrong Daruma Doll escapes, you lose a life. This would really pair well with a much slower initial speed.
Anyway, this is a fun game! Well done!