You can also access through the actual itch page of the game too. But here's the information also:

Mobile:
Directional buttons to move.
B or A to jump.
Top red button changes directional button layout.
Top gray button is select.
Bottom gray button is start.
Bottom red bottom goes to menu.

Web browser:
Directional keys to move.
Z or X to jump.
Enter is start button.
Shift is select button.

NOTE: On the mobile/web browser version, the music/sfx will not start until you click/tap the screen. Once you do the music/sfx will start, but lag behind. Go to the menu (ESC button or top red button) and reset the game. Then it'll be back to normal.