Just refresh the page if the thumbnail doesn't show the first time. Pretty basic. - Left/right arrow keys to move. - Up arrow to jump - You know what to do with red. Avoid it. - Hold up and the left/right arrows to wall jump. - Collect all the collectables to open the exit. - And you obviously know what the exit does. :P
The only thing you need to note is that this also has WASD and mobile support! Oh, also, a quick warning: Level 2 is quite difficult/impossible on mobile. :S