a faceroll is when playing a video game, to use one's face on the keyboard to play the game instead of using one's hands.
(See alternate definition for etymology relating to World of Warcraft and one very specific meaning.)
This is a hyperbolic, humorous term used to imply that certain kinds of play are overpowered (i.e. unfair), very easy (again in contrast to others), or are marked by being devoid of any strategy. That is to say, you can play the game successfully (1) without looking at the screen and (2) by hitting random keys (with your face.)
The term faceroll can be used as generally derogatory or inflammatory, as it is essentially a personal attack devaluing the video game developers's judgment.
Evolution of the use of the term into gamer lexicon demonstrates the term can simply be used humorously as an absurdity (to alleviate tension rather than create an indictment.)
--In context of World of Warcraft--
"I played a Paladin once. I started playing, and then rolled my face over the keyboard. When I looked up, I was in Outland."
(This comment suggests that 1/3 of the game content can be completed using a Paladin character in one faceroll. This comment is witty and humorous as an absurdity, because it would take ~50-60 hours of play time to complete this task.)
"We don't need to use crowd control in this dungeon. We can just faceroll it."
(This player is arguing that the dungeon is so easy, the group doesn't need to pay attention to what they are doing.)
A toon is a synonym for a character in a video game that is a role-playing game, usually used only in the context of Massively Multiplayer Online Role-playing Games (MMORPG), such as World of Warcraft.
Character, avatar, or toon are synonyms in this context.
(Avatar is a misnomer, however.)
In role-playing games, a great deal of effort is spent in creating a unique persona or character before play begins. During character generation, the player makes choices that will affect the gameplay, such as appearance, name, gender, race, and class. Once created, these characteristics are immutable, as they define the play experience. The selection of class determines the strategies the character will use to succeed.
In short, Role-playing games have great replay value because a player can re-experience the game using a new character or toon.
Toon is presumably a contracted form of cartoon; video game characters are animated, after all. The origin of this term can be attributed to the standard root of all leetspeak (internet jargon): a need for efficiency for lazy typists.
Toon is probably used because it is shorter and easier to type than the word character. Anyone familiar with these games can easily surmise the meaning of the term from context. Furthermore, the term avatar is avoided as it can possibly create confusion. In roleplaying games, avatar also refers to the incarnation of a deity.
I have 6 toons, so I have all the professions spread among them and I can craft anything!