At first I didn't understand that I could chose any red number to change. Once I realized this, it changed everything. I didn't read the game description so was a bit confused at first when all the numbers turned red. I didn't even know you could click the red numbers. I wish you had a tutorial in game explaining this mechanic a bit more clearly.
With that being said, this is my favorite entry so far. Absolutely brilliant idea. This is going to be a tough one to beat.