the music was pretty cool and i like the minimalistic style.
the right-click menu with all the upgrades is a bit unintuitive. i think the gameplay can be spiced up by simply increasing the speed of the player and the opponent.
and it is it not so obvious how to gain energy for a dash. especially when you reach 0 energy you cannot dash anymore, thats a bit mean. maybe store the energy and then release it
other than that, nice work :)