You can possibly lock your opponent's monster zone if he/she has no tribute monsters. Use Floodgate Trap Hole when your opponent Summons a Monster. Then disable the 2 remaining zones by using Ojama Knight's effect. You can then wait to get the cards that you needed or burn your opponent.
The text "monster(s)" on Floodgate Trap Hole means that it can affect multiple cards. See these screenshots below for example.
Canadia is flexible whereas Floodgate is good at locking opponent.
Today I beat some whale who has 3 of this cancer, with him having successfully having used all 3 on me during the duel. That felt great. An UR in a large box that's like the second worst of the game, and there are people who have 3... what the hell is wrong with the world. Whoever I see using more than 1 of this, be ready to have one hell of a tilt duel as I will pull the most cancer tactics possible.
Implying Konami doesn't have enough money to keep this game going for quite a while as F2P with all the money they've wrung out of people over the years. They aren't EA bad by any means, but they sure are striving to be if the newest ""Metal Gear"" game is anything to go by.
Anything that Rose Lover special summons on the field on the SAME turn the effect resolved will be immune to trap effects. Most likely, your FGT was used on a monster with the above immunity, hence it seems to not work on a specific Sylvan monster.
Why does floodgate not work on monsters summoned by amazones onslaught?