Simon says game completed on logisim

This is the famous Simon says game. You can play it in low graphics here. It's a difficult memory game and interesting to all ages. In the beginning of the game a random button lights. You have to press that button. Then the game gives you - by lighting the buttons - the same sequence of buttons adding 1 random in the end. For example if it gives you yellow blue yellow red and you re-enter them correctly the next will be yellow blue yellow red AND 1 random button (yellow/blue/red/green).
I've made this game using logisim. I used only logic gates (and/or/not/xor) and some splitters, adders and d-flip-flops without editing the clock's path. I also used 4 buttons and some leds to make the game user friendly. The whole project took me nearly 2 days.