And also remember this ruling
You cannot activate "Barrel Behind the Door" in a chain with "Ceasefire" if a) there are only face-down monsters on the field or b) The only face-up monsters are Normal (Effectless) Monsters.
You can only chain "Barrel Behind the Door" to "Ceasefire" if there is at least 1 face-up Effect Monster.
Reason: There is no guarentee that "Ceasefire" will inflict damage unless there is at least 1 face-up Effect Monster. In that case, the exact amount may not be known, but it will be "something". In the other instances, it's possible that "Ceasefire" would inflict no damage so the condition for activating "Barrel Behind the Door" would not be met.
- A