Nice one! Black is down a pawn, so they can't afford to just sit idle and wait for white to convert (which they surely would)
1...c5 2.Kg2 c4! is an important breakthrough that white can't ignore. 3.dxc4 Now white's extra E pawn is useless. 3...Ke7 4.Kf2 Kd6 5.Ke2 Kc5 6.Kd3 Kb4 Zugzwang 7.c5 Kxc5 8.Kc3 draw