Move the characters to the end of the level, collect the keys to open the doors. At times, you will need to cordinate with your twin in a slightly different world, looking to make it to the end doors. Despite only having 8 levels, At The Same Time is a clever, polished game wroth the time. Turn the timer on in the menu and see how fast you can complete all 8 levels, for the best speedrunning experience.

http://armorgames.com/play/18600/at-the-same-time