This is a truly fun little game, i love just passing an idle few moments on it when i'm waiting for virus scans or whatever to run. I think maybe a stamina bar might make the game a little more tactical, so that you have to conserve stamina in order to make big jumps and too much jumping leaves you weaker.
It is possible to use the walkthrough and still obtain the achievement. Simply use a separate browser to use the walkthrough, for instance i played the game on firefox, but used the walkthrough on windows internet explorer. Apparently they don't know my deepest darkest secrets.
the way i see it is not that you're playing games against a zombie, it's more a representation of you running from a zombie and the zombie giving chase. well, that or a poorly considered premise for a boardgame.