I found a little glitch, i fully upgraded core on the character you control, but it was still walking the same speed, then when i got the max upgrade for collect coins it started moving fast, so what i'm saying is it didn't upgrade my walking speed until i fully upgraded collect coins, is this a glitch or is it meant to do this?
At the start of the game, if you stand to the left of the block, so the left hand side of the block is parallel to the left hand side of your character, the coins go straight up and straight back down so you only have to jump :)
Tip for runner mode! To get 200 meters in runner mode easily, get the rebound gun, and fully upgrade it, then aim at the ceiling and a little to the right of your character and leave it there while jumping and avoiding gaps, this should kill nearly or will kill everything in your path :) so as long as you dodge the holes you can get far :D
To people who havnt got the medium badge, i didnt either. but wait a few minutes on the screen with your score and it gave it to me so it should to you :)