You've got the hang of it yea. Basically, the idea is that the number on the top left is the most important one. It tells you how many notes can be in one combination. Let's say this number is 2, then when you play 1234 we will look at this as the following combination of 12, 23, 34, simply said we split it into pairs. When you play 5'34'1 next you'll lose points because you have already played pair 34 previously. This number will get larger as the number of maximum notes increases as it would be more difficult for the audience to understand that you have repeated something when you play something very long. Thank you for the feedback! I hope you had lots of fun playing!
Will check out your game, of course, no problem!