‘Five Minutes’ is an extraordinary interactive HTML5 experience that is presented as a game within a One Page website. Players have to stop the main character from turning into a zombie by keeping him focused on his memories, which raises the stakes of the game, involving the user directly into the story. Nice touch as well with the .gs domain extension. There is not much more to say other than this is possibly the best 5 minutes you will spend online today. Do it.
This website has unfortunately been redesigned or gone offline, so I have removed the direct link to it. The screenshot below hopefully preserved enough of the design but if you are really keen to inspect further, try this Archive.org link. FYI: the site was first featured on 19 November 2014.