In Magic: The Gathering, infect damage is a type of damage that causes the player or creature to get poison counters instead of losing life points. When a player or creature with infect deals damage to another player or creature, that player or creature gets poison counters equal to the amount of infect damage dealt. If a player gets 10 or more poison counters, they lose the game.
In Magic: The Gathering, lifelink allows a creature to gain life equal to the damage it deals when attacking.
Infect is a replacement effect, meaning it modifies how the normal game rules work. Infect specifically modifies the damage-dealing rules. A creature with Infect does not deal regular damage to creatures or players. In the case of a creature, it places a -1/-1 counter on it for each point of unprevented damage. In the case of a player, it places that many Poison Counters. This is for combat damage and effect damage too. If a creature with Infect deals damage to a Planeswalker, as a Planeswalker is neither a creature nor a player, then the damage is handled normally. The Planewalker's own replacement effect will removes some of his or her loyalty counters.
In Magic: The Gathering, combat damage is dealt to a player when a creature attacks and isn't blocked. The damage is equal to the attacking creature's power. The player loses life points equal to the damage dealt.
In Magic: The Gathering, the mechanic "redirect damage" allows a player to change the target of damage from one source to another. This can be used to protect important creatures or players from being damaged.
No, lifelink does not work on planeswalkers in Magic: The Gathering.
Yes, lifelink works in Magic: The Gathering when a creature with lifelink is blocking. When that creature deals combat damage, its controller gains life equal to the damage dealt.
In Magic: The Gathering, the "damage redirect" mechanic allows a player to choose a different target for damage that would be dealt to a specific creature or player. This can be used strategically to protect important creatures or redirect damage to a less valuable target.
In Magic: The Gathering, double strike allows a creature to deal combat damage twice in a single combat phase. This means it deals damage during the first strike combat damage step, and then again during the regular combat damage step.
When a creature with trample is blocked in Magic: The Gathering, it can assign excess damage to the defending player or planeswalker if it has enough power to destroy all blocking creatures.
In Magic: The Gathering, trample protection prevents a creature from being dealt damage by a creature with trample if the damage would be lethal to the protected creature. This means that the protected creature will not take any excess damage beyond what is needed to destroy it.
In Magic: The Gathering, the mechanic "sacrifice a creature to deal damage" typically involves a player sacrificing one of their creatures in order to deal damage to a target, such as a creature or player. This allows the player to use their creature as a resource to inflict damage on their opponent.
In Magic: The Gathering, when you block multiple creatures with one, the blocking creature assigns its combat damage to each attacking creature it is blocking. The attacking creatures can divide their damage among the blocking creature as they choose.