I went for something a tiny bit differently: This should be read as a wiki article about the game, and as such some things are not fully described (given that they would have their own articles) but I hope that context and naming make everything clear enough for a casual read.

[color=lightcoral][u]Underlined and colored[/u][/color] terms would be links in the wiki article.

[hider=Marcus Goldstein as Zone Master]
Marcus Goldstein is pretty much defined as ‘difficult but awesome’. Purely by base stats he is weak with especially abysmal move speed, small hitboxes on his fast attacks and only okay defense and offense. Heavy knockback is the only thing going for him. However his special abilities make up for this as played competently he becomes one of the most lethal [color=lightcoral][u]zoners[/u][/color] available. Unlike most characters that have both a fast attack and a heavy attack, Marcus has only fast melee attacks available. His base heavy attack is an aimed shot from his revolver. Things change however with stick inputs plus heavy attack: This activates his strongest and most unique abilities, the ‘markerlight’ [color=lightcoral][u]traps[/u][/color]. Marcus can place many different kinds of traps that last a short while. Said traps are widely considered to be some of the best in the game. Unlike most traps, markerlight traps cannot be disabled by [color=lightcoral][u]projectiles[/u][/color] so an opponent must wait until they time out. Second, almost all markerlight traps have knockback of some description that allow them to be used in combo’s. Thirdly and most potent, not all of his markerlight traps are dependent on Marcus’ position on the stage. The traps themselves appear on-screen as crosshairs aimed at a specific spot with different kinds of crosshair indicating what kind of trap is in place. Their high visibility is more than compensated for by their utility.

The markerlight traps are:
Down + Heavy: [color=lightcoral][u]Suppressive Fire[/u][/color] - Places several traps in a line in front of Marcus. All have light damage and moderate knockback.
Forward + Heavy: [color=lightcoral][u]Precision Shot[/u][/color] - Places a trap at the opponent’s predicted position after 0.5 seconds. Moderate damage and knockback.
Back + Heavy: [color=lightcoral][u]Killzone[/u][/color] - Places a large area trap in front of Marcus that triggers a burst of moderate damage and knockback machinegun fire at the target area.
Up + Heavy: [color=lightcoral][u]Grenade launchers[/u][/color] - small area trap in front of Marcus that triggers a high damage and knockback explosion.
Down, Forward + Heavy: [color=lightcoral][u]More Dakka[/u][/color] - Places several traps at once in the air in front of Marcus. Moderate damage and knockback.
Down, Forward + Heavy, Up + Heavy: [color=lightcoral][u]Even MORE Dakka[/u][/color] - Like More Dakka, except now with more traps that also cover a bit behind and above Marcus. It is slower to execute in return. Moderate damage and knockback.
Down, Down + Heavy: [color=lightcoral][u]Incendiary grenade[/u][/color] - Creates an area of flames in front of Marcus that damages anyone standing on them. No knockback.
Back, Forward + Heavy: [color=lightcoral][u]Dance For Me[/u][/color] - Places a trap directly underneath the opponent. Takes a moment to arm. Moderate damage and knockback.

Playstyle: New players often try and use Marcus’ Markerlight as either pseudo-heavy attacks, slow projectiles or as long term traps. The first is a tremendously bad idea due to Marcus’ low speed. As far as the second idea is concerned, there are a lot of fighters that are a lot better at projectile work and clearly outclass Marcus in this department. Finally the markerlight traps usually do not last long enough for the third strategy to really work. It is simply impossible to cover a stage in traps, as they time out too fast. The playstyle Marcus demands is a highly unique, tricky but extremely potent type of zone control.

You must always force characters to approach Marcus via your preferred avenue, not theirs: Use More Dakka to punish aerial aces like [color=lightcoral][u]Weiss Schnee[/u][/color] and make them come at you from the ground. Against characters that cannot jump very well both Suppressive Fire and Incendiary Grenades are great. Incendiary Grenades is best for denying ground while Suppressive Fire should be used in conjunction with other traps that can make the most of it’s knockback. In short you should get in the habit of using Markerlights as weak heavy attacks that have a hitbox that stays in place for a massive period of time.

The second step to mastering Marcus, and the real key to his playstyle is the ‘[color=lightcoral][u]congaline[/u][/color]’ tactic. With some careful positioning it is possible to force/launch the opponent in one trap, where the knockback launches them into another, which launches them into another, and so on and so on. As an example, three Suppressive Fire traps spaced just right are, even with the increased [color=lightcoral][u]knockback scaling[/u][/color] of [color=lightcoral][u]patch 1.14[/u][/color], eighteen guaranteed hits on [i]any character[/i]. 

During combos Marcus can [color=lightcoral][u]juggle[/u][/color] opponents like no other, especially with Precision Shot. Placed at the start of an [color=lightcoral][u]air[/u] [u]combo[/u][/color] even characters with speedy recovery are guaranteed to take at least two hits before knockback scaling kicks in! However, starting combos is very tricky with him. Out of all of his melee moves up + fast usually works best as it offers the best balance of speed and knockback. Against slow opponents Dance For Me is also a useful opener as they cannot always [color=lightcoral][u]break out of an animation[/u][/color] fast enough to get away before it arms. Remember to never try and [color=lightcoral][u]rush down[/u][/color] your opponent! Marcus has neither the speed nor the offensive power for it!

An oddity about the markerlight traps is that some of them are counted as projectile attacks but can’t be [color=lightcoral][u]reflected[/u][/color] back. A character with the ability to reflect damage can prevent the damage dealt to themselves, but Marcus will not be hit either. The traps in question are Suppressive Fire, Precision Shot, Killzone, More Dakka and Even MORE Dakka and Dance For Me. Note that players trying to cheese their way through your traps like this are very vulnerable during their [color=lightcoral][u]recovery frames[/u][/color]: Even Marcus can punish them if they reflect a trap rather than dodge around it when the fighters are close enough to one another.

Of special note are teleporters such as for example [url=http://www.roleplayerguild.com/topics/77164-heroes-of-beacon-contest-of-champions/ic?page=2#post-2552240]Oswald Connoly[/url]. Always stick close to your traps to make sure that them teleporting towards you is a death sentence for them!

[color=lightcoral][u]Level 1[/u] [u]Super[/u][/color]: Stay On Target! - A large crosshair appears at the centre mass of an opponent. The crosshair is controlled by stick input and stays on screen for 3 seconds. Every 0.5 seconds an attack similar to Precision Shot lands on the crosshair for a total of 6 attacks. A single hit does only moderate damage, however all 6 combined do enough damage to make [color=lightcoral][[u]Gren Oak[/u][/color] proud.

[color=lightcoral][u]Level 2[/u][/color] Super: BFG Strike - A single projectile comes in from above, hitting in the exact middle of the screen and exploding. Mastering a congaline that ends with an opponent hit by this attack is considered a rite of passage by many players that have Marcus as their main.

[color=lightcoral][u]Level 3[/u][/color] Super: Point Blank Annihilation - The source of all the Markerlight traps appears: The [color=lightcoral][u]Elegantly Unsubtle[/u][/color] rolls onto the stage from the side and fires a single, devastating shot in a horizontal line. This ability is best used at the end of a congaline as all characters can dodge this Super simply by ducking.
[color=lightcoral][u]Instinct Mode[/u][/color]: Improved Tracking - Marcus instinct mode only affects his markerlight traps rather than himself: They start to very slowly move towards an opponent, and their hitboxes are increased in size. As the moving traps mess up the set up for congalines it is actually considered to be an overall decrease in combat ability rather than an increase. However several competitive level players have successfully set up unique congalines with the shifting traps, including Pat007’s infamous ‘endless dakka death conga’ (said congaline is no longer possible after patch 1.14). 

[color=lightcoral][u]Fatality[/u][/color]: Marcus has what is widely considered to be one of the most amusing fatalities in the game: While the opponent’s character is stunned he hops on boards the Unsubtle. Subsequently a chase begins where the opponent can choose to extend the life of their character by running away in a [url=https://www.youtube.com/watch?v=qPMIQobB3ZM]temple-run[/url] like minigame. After 10 seconds though the Unsubtle’s cannon fires regardless of the opponent’s performance and the match ends (this is not an outcome set in stone: By entering ‘RUNRUNRUN’ as a player name players can keep playing the minigame until they either mess up or Marcus’ player fires the cannon manually by pressing an attack button).[/hider]