Need to convince a programmer, is there a tutorial about that in stackoverflow?

So here we are, me and Ionthas (the programmer) finishing up some details of our entry. It's a SingStar-Guitar Hero kind of game with a twits for the absurd and random kind of humour... well it's hard to describe. The thing is, I'm trying to convince him to put an extra horde zombie mode, which is totally pointless and would mean that he would have to skip sleep hours (tomorrow we work), also has nothing to do with the theme lol.

Help me, I need convincing power.

Random picture because why not Capture.PNG