First you should add a sound when you have to accept the game because a lot of people just don't realize they have to accept the match.
Then you should fix it so that if someone leaves the match he can join back , everytime i try to join it says unable to contact server and my friends are on the server.
Then you also need to fix ranks atleast on the first 10 matches to get your rank you had to restart your game after every match for it to count, now with rank i don't know if it's the same don't even know if it is possible to rankup or derank , have played about 10 matches after having rank and still haven't ranked up or down.
And if possible tell us what ranks there are , I've been looking for information about the ranks and can't seem to find any ... What ranks are there ?
Ah and try to add a cooldown for people who leave competitive matches , so that if they leave they get banned for a while .