Can't believe I made this 3 years ago
doesn't seem that long ago.
If I remember correctly I stored the player's position in an array. When an echo is spawned it starts a timer that adds to a instance variable then I used that variable to get the player position in the array.
That's why the game preforms badly, that and Construct 2 & HTML5 where pretty new at the time. If I looked into it now I could probably get the game to run better as Construct 2 & HTML5 have come on leaps and bounds.