Damage Gate lets you Special Summon a monster from the Graveyard with less ATK than the battle damage you took from an opponent's attack. With that being said, Labyrinth Wall has 0 ATK, so you can special summon it after taking any amount of battle damage.
Using this card's effect, you can set Labyrinth Wall face-down without needing any tribute. This will keep it hidden, making your opponent unable to switch the position and attack it first to flip it up.
Amarylease's effect only applies to normal summons. Face down summons still need a tribute, so you would be putting a 0 ATK card in harm's way. You need something to change the card's position on the same turn you summon it.
-Pumprincess the Princess of Ghosts/ -
Wonder Balloon (to reduce attack)
-plus, any card that increase the labyrinth wall's defense, or reduce the opponent's monster attack. (+defense, -attack)
or Soul Exhange to set down another wall.
- summon the wall
- set the trap cards
- set, or activate Canyon
- set down any monster dummy, your choice. I prefer Crystal Seer, and
- They attack, activate Staunch Defender, choose the wall, and BAM. any damage will be DOUBLED, with Canyon.
ahh, yes. Exactly. That's why I said before, this deck is stupidly easy to counter.
There're tons of ways to destroy the wall, and it'll be sitting duck.