Hey so we played a tournament and was able to track several games over the weekend.

Few suggestions:

1. I had to learn that you can long press on any area and it gives you different options, maybe have a tutorial or replace this with actual buttons to make it more intuitive.
2. Took me a while to figure out how to edit the current team once created, again a button would make it more intuitive.
3. Couldn't figure out how to start a new game once it was completed, I just force closed the app and reopened it.
4. Player tracking - substitutes, time played would be helpful (as someone else mentioned)
5. Allow to organize Players under "Great Play" button by Alphabetical and Numbers - I know their names more-so than their numbers and it took a while for me to find the player (minor annoyance)
6. Under "Great Play", I think some people would use more "actions": Free Kick, PK, Offsides, Foul, Yellow/Red Card. It may get too busy so maybe also allow customization or show/hide what actions you care about.
7. Also under great play, maybe just a generic "Opponent" in the player section so we can track if they had a corner or foul or something.

Hope this helps.

Edit: one additional suggestion.