It is a two player game whith one tagger and one runner. You can recognize the tagger by a red dot
on his head


The person who is tagger 

while the timer is at zero has lost.

the black player moves with a, d and jumps with spacebar
you can also change the gravity by pressing s

The white player jumps with the upper arrow key

and moves with the arrow key.
this player can too change the gravity by pressing down arrow
play the game on itch
https://real-dragon-games.itch.io/dark-vs-light-demo