There's no "Undo" button, but you can save the things before proceed, so after "Saving" and doing your stuff, if it was all right you can proceed, but if there's something not right use the "Load" Button. =)
Me:
sometimes you will need to say yes or no
God:
What makes you say that I will need to say yes or no.
Me:
for a awser
God:
Is that among the best things you can say?
Me:
yews
God:
What were we talking about again?
Me:
pies
God:
Oh yeah, now I remember.
 "Faça a bruna cair.")
 "Harmonia Chat")
 "Fantasy Offline")
 "The Sandbox")
 "Fantasy Online")
 "Step Seq.")
 "Zombie Outbreak Simulator")
 "Anti-Idle: The Game"){kind=logo}
 "Kongregate Chat")
 "Icy Gifts")
 "my first platformer- the obstical corse")
 "Lucky Tower"){kind=icon}
 "Road of the Dead")
 "Mercenaries 2: World Nearly In Flames.")
 "Clearsave animation")
 "iGod")