You should be on the lookout for the number in the top left. This tells you how big a combination can be before the audience notices you are repeating something. Let's say that number is 2 then 1234 would be 12, 23, 34, and if you then do 5126, you repeat 12 in the middle, for example. It is not the whole line of notes that you shouldn't repeat, but the little pairs.
I'm glad you liked it! Thank you!
Yes, I will check out your game. It looks fun.