Each colour is associated with a strategy: Steel hits hard, Sapphire is slow and strategic, Ruby hits fast but weak, Emerald is about thinking beyond the playing field, Amythest nerfs your opponent and Amber heals and buffs your deck
(You are way behind if, at any point during this turn, an opponent had 10 or more life than you, controlled at least three more creatures than you, or had at least three more cards in hand than you.) To determine if you are way behind, check the game state as it was at any point during the current turn, regardless of whether Knight of Lost Causes was on the battlefield at that time
If you guessed correctly, Blufferfish gets +2/+0 and can't be blocked this turn
Hydras Growth Hydra's Growth starts off slow, giving just a single +1/+1 counter
Monastery Swiftspear is a staple of a lot of aggressive Red decks, because it only costs one mana, has haste and gets +1/+1 whenever you cast a noncreature spell