The skateboarder of Street Sesh is controlled with the directional keys, but he can also perform maneuvers. The space bar is used for jumping, the X key for tail-slides or 360 flips and the Z key for kick flips and 50-50s. Street Sesh is a 3D game, so the graphics are better than what you would expect from a flash game. The gameplay is linear, you just have to go downhill and perform as many tricks as you can. You will have to jump over many stairs and if you don't time your jumps correctly, you will fall down. This will make you lose momentum, but it won't bother you in any other way because the game is not timed and you can't hurt yourself. You will also have to skateboard through some busy streets of Street Sesh, but no vehicle will hit you because they are stationary. The key is to perform as many tricks as you can, whenever you can. You can find ramps, benches and even escalators on which you can tail slide for extra points. Another interesting fact about Street Sesh is that you won't lose your balance even if you are performing a long slide on a railing.
If you want to increase your score, you can always look for the yellow boxes which are floating in mid year. If you get one, your current score will double.