I think you can't. Floodgate can only be used when your opponent (a player) special summons a monster (meaning it only responds to inherent special summon).
Silent Swordsman LV7 can only be special summoned with a card's effect. It's the card's effect that special summons SS LV7, not the player.
Someone please correct me if my above reply is wrong, because Yugioh for whatever reason has a fairly complex ruling just for responding to a summon lol
It can be used against him. It says "Summons" which includes normal and special summons. Whoever says "Inherent special summon" is wrong. It works on all summons bar Blizzard Princess.
Floodgate works on literally everything. Including God Cards. Because it activates one step after the special summon/summon itself. Whether it's inherent special summon or not, the Floodgates will activate. Reason why it works on every other LEVEL UP arch type card as well.
Yes u can. Trap hole series works in responding the summon. However, u cant use card like solemn series because those card NEGATE the summon itself. It cant negate summon which is came from another card effect, be it from level up or silent swordman level 4( well, u can negate the spell, but the silent swordman itself never really reach the field, in that case)
Hey I'm anonymous above you, my reply is for the anonymous who said "Hey I'm anonymous above you, my reply is for the anonymous who said "Floodgate works on litterally everything including God card"
Hey I'm an anonymous above you, My reply is to the anonymous above you, my reply is to the anonymous saying you want to reply to the anonymous above you. The way you keep saying that makes you all sound like a bunch of 🔥tards.