I love Catalyst a lot, and it very well could be the recency bias talking, but she’s my favorite of the new playable characters added to Apex Legends during the battle royale’s fourth year. The ferrofluid-wielding defender isn’t a force to be reckoned with–Catalyst won’t be breaking the competitive meta anytime soon–and her story hasn’t posed any groundbreaking lore ramifications yet. But none of that matters when Catalyst plays a lot like the legends added in Year 3, all of whom celebrate the best part of Titanfall 2’s legacy: A first-person shooter doesn’t have to make practical sense to be a whole lot of chaotic and joyful fun.

Added in Apex Legends Season 15, Catalyst doesn’t have especially powerful abilities, but they certainly seem so with all the visual flair assigned to her kit. And all those flashy skills have one thing in common: They allow Catalyst to be an absolute menace when it comes to opening and closing doors. This may seem dumb and unimportant, and if Catalyst were a playable character in any other hero shooter, it probably would be. But Apex Legends is different–it has the best door technology I’ve ever seen in any video game to date. Adding a character who can mess with a system that’s that consistent has a lot of fun potential.

To better understand what I mean, let’s talk about Apex Legends’ doors for a second. I want you to think about doors in video games. How do most of them work? Honestly, they don’t. There are a lot of doors that simply signify the moment when the game takes control away from you and sees you move to the next area via a short cutscene, some are a loading screen between areas, or they’re not even there and the game uses empty entryways. In the cases where doors are allowed to be doors, there are usually only two states to the door–open or closed–and the door cannot be interacted with beyond moving it between those two states.

Apex Legends goes the extra mile. There are five rules to remember when dealing with doors in Respawn’s battle royale game.

1. A door is a physical object in the in-game world.
2. You can see through the glass panes of a door.
3. When interacting with doors, you can only push them open.
4. Doors can be partially damaged and fully destroyed.
5. Doors cannot be rebuilt.

These tenants are important because they shape what is often referred to as the “door meta,” informing how every situation regarding a door can transpire. For example, a Crypto drone can only push a door open as doors cannot be pulled, and to use a door as a ledge to climb up to a building’s roof means you need to open the door from the inside of the building so that it swings outward. Additionally, as all doors are regarded as physical objects, they will stop opening if they encounter another physical object (such as a player or deathbox), giving every door multiple states between being fully open and fully closed. A door that’s open a smidge vs. one that’s fully closed can be all the difference between whether a bullet hits its mark or an Ash has unobstructed line-of-sight to Phase Tear her and her squad out of a trap.

The last two rules are big, as they dictate the flow of combat when a firefight spills through a doorway. If you want to get through a door, the fastest way is to open it. However, you can’t open a door if another player is standing against it on the other side. This is called “blocking,” which describes the common practice in Apex Legends where you get inside a building and stand against the door, preventing a pursuer from getting inside while you heal up or reload. The best way to counter this is with melee attacks. The first attack against a blocked door will only damage it, but a second will fully destroy the door.

It doesn’t matter which legend is holding the door and which one is doing the kicking. It has always taken two kicks to destroy a blocked door. You can alternatively use an explosive–whether that’s a grenade or an explosive legend ability like Fuse‘s Knuckle Cluster–which will damage and destroy the door, typically hitting whoever is on the other side. But in regards to the last rule, once a door is gone, it’s gone for good. Regardless of how you do it, destroying a door ensures that you and your squad are losing access to using that same door for the rest of the match. The same rules apply for damage, meaning if you damage a door and then subsequently try to use it to block an enemy, you already know it will break down with one melee attack. There’s nothing you can do to fix it back up so it can take two kicks.

Anyone who has played Apex Legends can attest to the battle of wits that regularly occurs around doors, with opposing sides sizing each other up through the glass–sometimes for as long as a minute–as attackers try to figure out how best to get to the other side and defenders attempt to figure out how to best block the door. Do you go for melee attacks on the door, signaling your intent to the defenders on the first kick? Or if you’re the one blocking a door, how long do you hold it? Either side has the opportunity to take advantage of the other–for example, if you open a door as an attacker is mid-kick or taking out their grenade, it may allow you to get some shots off before they have a chance to pull out their gun again. Similarly, baiting a blocker to prematurely open a door means you’ve tricked them into giving up their bullet-proof obstruction. You could write whole guides on how to best respond to the frantic rock-paper-scissors showdowns that are Apex Legends’ doors.

Fighting against an enemy on the other side of a door has become a familiar dance over the first 14 seasons of Apex Legends–the rules governing doors have not changed and the ability to alter the door meta has not evolved, meaning no matter your squad makeup, you have always been able to interact with any door in the exact same way as anyone else. Characters like Fuse and Valkyrie can destroy doors with their abilities, but any legend can do that with grenades. Characters like Rampart and Caustic can block doors with their abilities, but you’ve always been able to do that with deathboxes or your own body. New characters didn’t change how players are able to interact with doors, they only added new means of the same strategy.

And then came Catalyst. Not only does her passive ability allow her to fundamentally change the rules of how doors work, but her tactical and ultimate abilities also allow her to affect entryways. Some legends have one ability that allows them to affect doors, and on especially rare occasions, you have a legend with two. But not Catalyst. She’s the first legend where all three of her abilities in her kit allow her to alter how an opposing squad has to approach a doorway.

With her passive ability, Barricade, Catalyst can reinforce doorways from melee attacks, meaning they take four mighty kicks to knock down instead of a measly two. Catalyst can also use this ability to rebuild doorways that have been destroyed. So right out of the gate, Catalyst breaks two of the fundamental rules of Apex Legends doorways. Because of her addition, you can’t expect every doorway to be broken in just two melee attacks anymore, and destroying doors no longer means those doors are gone forever.

Unlike Barricade, Catalyst’s tactical ability, Piercing Spikes, and ultimate ability, Dark Veil, don’t directly affect doors, but they do allow Catalyst to shape entryways. Piercing Spikes allows Catalyst to coat a spot with harrowing ferrofluid spikes, which conspicuously spread out horizontally just far enough to cover a pair of double doors. And then there’s Dark Veil, which is a giant wall of ferrofluid that blocks line of sight. At first, I thought it was odd that Catalyst creates the wall out from her in a line, as opposed to spreading out horizontally in front of her. It doesn’t seem the most conducive way to build a wall. But then my third eye was opened during a match where I opened a door and a Catalyst fired Dark Veil right at me. The wall came at me and out the door I had opened, dividing a simple doorway into two.

The full realization of what had transpired didn’t hit me until later when my poor performance in the subsequent fight left me dead on the floor. Without realizing it, I had internalized a sixth, unseen tenant: A door leads into one space. Which seems silly to even type out. Like, of course, a door always leads into one room. It doesn’t even feel like a rule. But when a character is added who can erect an opaque wall that will heavily slow and blind you if you try to pass through its permeable surface, Respawn suddenly provided us a way of separating a single doorway into two.

The fallout of such an ability is evident in how I was ultimately taken down: I hesitated. Instead of simply going through the now open doorway, I had to make a choice of going through the entryway on the right or left, and I paused for a second to think about it. It’s been a long time since a new Apex Legends character surprised me, but that moment really got me. One door into one room becoming two doors into two rooms is quite the escalation of considerations to examine in a manner of seconds. And I know it’s not just me because following the loss, I’ve used this exact strategy to absolutely wreck opponents as Catalyst. And we’re still limited to Broken Moon, the new map, at this point. Imagine what happens when the older maps come back into the rotation and Catalyst is able to use this strategy to disrupt the comfortable familiarity of doorways we’ve come to know and trust on long-existing maps like World’s Edge and Olympus.

Every season brings with it changes, whether that’s a new map, balancing adjustments, or a new weapon. But throughout it all, one aspect of Apex Legends has remained stalwart: the doors. And now seasons of muscle memory and tried-and-true breaching strategies have to be thrown out the window, all because of one character. Frankly, I couldn’t be happier. Injecting a little chaotic evil is thematically appropriate for Apex Games’ self-described “grim trans witch” with an attractive dry cackle, and it’s surprisingly fun to mess with opponents who are suffering through the same muscle memory conundrum I am. And that’s all I really want out of a new Apex Legends character. Sure, getting a new face who’s competitively viable is good every once in a while, but a new character who’s just a genuine blast to play because she can be an absolute nuisance to everyone around her is what keeps the game fresh and fun for me nearly four years later.