It is best to just beat a game and be done with it. Anything else is just a waste of time. When I played Kingdom hearts, there were a TON of side projects, all of which weren't even remotely required to beat the game. After I beat it, I started trying to collect all of the Dalmations, trying to make all of the items, etc. It was all a waste of time and nothing extra was accomplished by it. You could play on to beat a few special bosses, which was neat. Those extra missions are fine by me.