Attributes: Doom Slayer is an agile character, boasting both tremendous speed and power. He's surprisingly pretty heavy too, as heavy as Ganondorf or Snake for comparison. Doom Slayer's moves are very focused on securing early KOs and thus cause a lot of knockback. This comes at a price though... he doesn't deal damage the best and his recovery is pretty predictable.
Mechanic 1 - Glory: When land a move that causes a tremendous amount of knockback, enough to get an opponent in a magnifying glass, Doom Slayer is able to heal off some damage. This is mainly to resemble the Glory mechanic in the new Doom games.
Mechanic 2 - Ammo: In my moveset, all of Doom Slayer's smash attacks and all but one of his aerials uses ammo. If you have ammo, the attacks become more powerful. If you have no ammo, Doom Slayer's attacks are weaker; you will have to go on the defensive and wait until enough ammo refills or use the Chainsaw to recover ammo. To make things simple for Smash, all of his weapons use the same ammo so that you won't have to worry about ammo types. The max amount of ammo he has is 50; smash attacks use 5 rounds and aerials use 3 rounds. If you have less than 3 rounds, you can still do a smash attack or aerial normally.
Mechanic 3 - Armor: This is not super armor. When Doom Slayer has Armor, the Armor will absorb some damage and Doom Slayer will receive less damage like in the older Doom games.
Jab: Doom Slayer brings out a pistol and shoots as a flurry attack and it ends with an explosion. Like in Doom 2016, the pistol has infinite ammo and thus won't affect your ammo count.
Tilts: In all of his tilts, Doom Slayer will use the Doomblade, so his attacks are a bit disjointed here.
Forward: Doom Slayer punches with a hook motion.
Up: Doom Slayer does an uppercut.
Down: Doom Slayer does a punch forward, but it's more like a stab with the Doomblade.
His forward and up tilts are actually pretty powerful in terms of knockback. His down tilt is more of a poke for him that could hinder very linear recoveries.
Smashes: Doom Slayer uses his arsenal for his smash attacks. When you use a smash attack, it uses 5 rounds.
Forward: The combat shotgun is Doom Slayer's preferred weapon for his forward smash. It deals more damage and knockback up close and fires off a short explosive that is bit weaker.
Up: The rocket launcher is going to be Doom Slayer's friend for this smash attack. Like Snake's up smash, the longer you charge the smash attack, the farther it will go. Doom Slayer will also deal damage just by bringing it out, like Snake's again. Unlike Snake's up smash, the rocket won't come back to the ground and it explodes in midair.
Down: Doom Slayer takes his plasma rifle and shoots and slam down the weapon at the same time. The result is the weapon emitting an electric shockwave that surrounds and circles around him.
Throws: Doom Slayer's throws are all violent and vicious, just as you would expect.
Pummel: Doom Slayer grabs with his right hand, and punches with his left hand.
Forward: Doom Slayer slams the opponent to the ground, as if he was Banjo and the opponent was Kazooie during their forward smash.
Down: Doom Slayer knocks the opponent down and stomps on them.
Backward: Doom Slayer just throws the opponent behind him as if they were nothing.
Up: Doom Slayer does an uppercut, like a Mortal Kombat-esque uppercut.
His forward throw is the most powerful in terms of knockback, while his down and up throws are good to set up juggles.
Dash Attack: Doom Slayer does a Dash forward, punches with his right hand, and emits an electric shock. This is meant to represent the Blood Punch from Doom Eternal, so it's naturally very powerful.
Aerials: Aside from his neutral air, all of his aerials have him use his arsenal. His aerials are not as powerful as his smash attacks, but they are helpful in getting off-stage KOs. With or without ammo, Doom Slayer will do an additional move on top of firing his shots, so that he won't be completely helpless in the air.
Neutral: Doom Slayer uses the Doomblade and moves in a clockwise motion from the front of him to behind him. The best comparison I can give is Cloud's neutral air.
Forward: Doom Slayer does a forward kick while firing rounds from his machine gun. The knockback is weaker from the machine gun rounds, but is good at gimping very weak recoveries.
Up: Doom Slayer takes out his Doomblade and machine gun again and fires three rounds. The machine gun rounds are perfect for juggles while the Doomblade can help him secure KOs.
Backward: Doom Slayer does a kick behind him while pulling out his combat shotgun. Similar to his forward smash, it's much better when you use this move up close and personal rather than from a distance.
Down: Doom Slayer uses his rocket launcher and the rocket explodes from underneath him, causing a powerful meteor smash. This move actually has a unique property in that if it uses ammo, Doom Slayer will reach some height from this move and you can use when you are trying to recover; this is a reference to Rocket Jumping in Quake. Without ammo, Doom Slayer won't gain extra height.
Specials: All of his specials are based on their incarnations from Doom Eternal.
Neutral - Frag Grenade: Doom Slayer shoots out a Frag Grenade from his Equipment Launcher. With this move, you are able to aim in front of the Slayer in several angles. The max distance it reaches is about over half of Final Destination. In comparison to Snake's Grenades, the Frag Grenade is more powerful in terms of knockback when it explodes. What it makes up in power, it loses in flexibility; unlike Snake's Grenades, you cannot use the Frag Grenade as an item.
Side - Flame Belch: This move is how you get Armor. Doom Slayer's Equipment Launcher spews out fire for a short period of time and you are able to aim it in arc-like directions. Unlike Bowser's and Charizard's neutral specials, you cannot hold down this move indefinitely. However, the move does have a strong finisher in comparison to those moves.
Down - Chainsaw: Without having to wait for the ammo to refill, this is how you get Ammo. Doom Slayer brings out his trusty chainsaw and it has two charge related attacks. The first level is when you don't fully charge it and he just does a stab forward; the longer you charge it, the more damage and knockback you do. If you fully charge it, Doom Slayer holds the chainsaw over him and slams it downward; this gives the attack more reach, power, stronger against shields, more ammo, and even gains super armor. This move can be released early with the attack button and it cannot be cancelled. You could say it's better than Byleth's down special, but the chainsaw doesn't easily break shield's like Byleth's does.
Up - Meathook: Doom Slayer takes out his trusty super shotgun that he can aim in multiple directions. It's a tether recovery and he can latch onto the ledge or towards opponents. Unlike other tether recoveries like Joker's and Ivysaur's, the Meathook takes longer to come out and is thus more predictable. He can use 5 ammo rounds for a powerful shot while he's recovering or latching onto an opponent. When he latches onto an opponent with the Meathook, they get stunned, Doom Slayer goes towards them, and he can shoot at them with the super shotgun or go for a powerful punch attack.
Final Smash - BFG 9000: Say hello to Doom Slayer's... massive friend! Doom Slayer takes out the BFG and does one powerful blast out of it. The projectile goes in a linear fashion; anyone caught in the shot will be stunned, take tremendous damage, and then get knocked back while anyone close enough to the shot will take some minor damage. Anyone over 100%, whether they were caught in the projectile or were near the beam, will be automatically KO'd and Doom Slayer will heal off some damage thanks to Glory.
