[@main]
#IF
check [666] 0
#SAY
Would you like to kill the devil for me?\\
<Yes/@devil>\
<No/@exit>\
#ELSESAY
You have already killed the devil, go away\
<OK/@exit>
[@devil]
#ACT
SET [666] 1
#SAY
Well done you killed the devil\
Would you like to kill him again?\
<Yes let me kill him again/@killagain>\
<No thank you i have killed him enough/@exit>\
[@killagain]
#ACT
SET [666] 0
break
That looks right i think, note that this is the first time i have ever looked at flags, for about 10seconds last night before i went to sleep, they seem pretty easy so if that is wrong then tell me so i can correct myself.

hope it helps