Epic Games' Fortnite has had one hell of a year.

2017 saw Fortnite rise from hidden gem to household name, as popular among celebrities and sports stars as it is in playerbase numbers. This February it reached a staggering 3.4 million concurrent users, beating out genre trendsetter PlayerUnknown's Battlegrounds for the first time in series history.

After a lukewarm reception to the game's original, cooperative survival mode, last March saw the first playable release of Fortnite: Battle Royale, a player-vs-player deathmatch survival game. One hundred players drop from the Battle Bus onto a lush, vibrant island of rolling hills, sandy beaches, and tight clusters of buildings dotted throughout the map to battle it out for last person standing.

Inextricable from Fortnite’s popularity is its unique building mechanics. Everything destructible in Fortnite: Battle Royale drops materials, which can be crafted on-the-fly into walls, floors, and staircases. In pitched gunfights, players can throw up hasty constructions to act as impromptu cover, or elaborate towers and fortresses to wait out the tense endgame.

Both Battle Royale and the earlier, cooperative Save The World mode have not yet reached release, but are both available to play in early access using Epic’s launcher as development continues. Recently, Gamasutra sat down with Eric Williamson (Design Lead) and Zack Estep (Producer) to discuss how Fortnite: Battle Royale came to be what it is, and how the team brought it to life.

How did you arrive at the building blocks that went into Fortnite Battle Royale? Were there any assets or designs that you wanted to implement but didn’t, or couldn’t?

Eric Williamson: So there’s a couple parts of my answer for this. First and foremost, when we started Battle Royale, we had this tremendous starting place from the Save The World campaign that we could use as our sandbox to build on top of.

We wanted to create Battle Royale in a relatively quick timeframe. One of the things that we intentionally said upfront was that no one’s on the team’s allowed to say “what if”.

What we meant by that was that because our timeline was so short, and we wanted to create a playable version immediately, it wasn’t “hey we could do all these crazy things” it was “what can we do, and how can we get it done as quickly as possible.” It wasn’t pie-in-the-sky land. Naturally, that meant that lots of ideas we had didn’t really get fully explored.

As we continue to update and iterate on the game, we’re adding new items, new systems, new consumables, etc. Those are some of those ideas that we had way back of like, “hey what if we wanted to do something like that?”

You mentioned how you were building off of the base of the STW mode, and obviously you had something of a crunched timeline. What was the process of converting that into a battle royale mode, in a design sense?

Eric Williamson: Where Battle Royale is at now, there are a lot of decisions that appear deliberate or may seem obvious, but during the initial development period were still sort of questions. For example, the decision to go with a more natural flowing terrain is a little bit different than Save The World.

Our weapons and weapon tuning as well as the details of our weapons systems—some of that progression isn’t present in Battle Royale. There are a lot of traps that are available in Save The World, and we have a very small subsection of that. It was a deliberate but also time-constrained decision-making process of what we should do and what made the most sense.

Were there any things you were specifically looking for or avoiding when taking design assets into Battle Royale?

Eric Williamson: One of the targets that we had very early on was that matches needed to be a reasonable duration: 18-25 minutes or somewhere in that ballpark. We didn’t want it to feel like it was going to be a huge commitment when you hit the play button. We had to evaluate a lot of gameplay systems and other things under that lens to determine “does this make sense?”

For example, Save The World has a crafting system that allows you to create things. We considered some parts of that early on, but we felt like if the matches were going to be relatively short, how much time did you want to spend crafting something, rather than scavenging and finding things and engaging in combat?

We had to be very selective about what types of gameplay that fit in a longer experience that Save The World provides, but doesn’t fit in a shorter and more digestible match that Battle Royale provides.

Zack Estep: One of the tenets we had were to make sure stuff was very relatable, across the board. Everything should make sense when you pick it up, or when you utilize it, or through exploring the world. We didn’t want anything that required several sessions of you experiencing that thing before you could mentally grasp it.

It was a lot of easily mentally-mappable content like that—easy to pick up, harder to master.

Fortnite is a huge game on Twitch, and people are talking about competitive Battle Royale. Was that a part of your design process or were you more focused on casual players?

Eric Williamson: It’s a silly thing to say, but we were so focused on fun and making the experience enjoyable above all else that those are kind of happy accidents along the way. It’s great we have that exposure on Twitch and that people are picking up the game as they are, but the core for us was focusing on the fun, and making sure it puts a smile on your face.

In comparison to other BR games, Fortnite is the most prominent with a building element. In your design process, did you think that building would change a player’s approach to the game?

Eric Williamson: Very early on in our prototypes it was really a little unclear how players would use building. In our internal playtests, players felt initially like “why would I build a base if the storm’s going to close in and I can’t use it?”

Over time that’s evolved into “I can build cover very quickly,” or “I can build a base very quickly” and it’s considered a throwaway base—when you’re done with it you move on, you go to the next place.

We certainly hoped that building would be a core component of the mode, but until we were in the first month or two of being in early access, we weren’t quite sure how that would evolve and if the top tier players would use it as much as we had hoped they would.

You watch some of these amazing videos of the best builders out there, and you see the dialogue or conversation that they have when they’re fighting somebody else. The strategy they use in how to approach that engagement is really incredible.

Being able to build as a player means that combat isn’t just a couple shots and someone’s dead, it’s this conversation that occurs over sometimes even a couple minutes, and in some ways it’s like watching an artist try to paint with a building paintbrush. It’s really quite incredible to watch.

In a recent update you introduced an alternative style of building, the turbo building mode.

Eric Williamson: Yes, it allows players to build much faster by not requiring a separate click for each building piece.

Zack Estep: Yes, we enabled turbo building, auto material switch, and allowing you to build with less restrictions all with Season 3, that was all done recently.

Less restrictions?

Zack Estep: Previously you were put into a position where if there were obstructions in your way you first had to destroy them. Now with the same logic that you can build through hills and mountains, you can build through trees, rocks, and some other obstructions.

You cannot build through pre-existing structures, but we’ve rolled back some of the logic there for the building system.

Another thing announced recently was the 20-player team mode. After the fifty-on-fifty mode, what made you want to look into a smaller team?

Eric Williamson: We think that limited time modes are a really good way to keep things fresh. We’ve done a couple different limited-time modes so far—Fifty-vs-fifty was our first one, we’ve done a rocket launcher and grenade only mode, we did a sniper rifle mode, we did a stealth mode… it’s a real fun way to do something that isn’t permanent but it’s fun, and it keeps things fresh.

We saw this as a natural evolution from the fifty-vs-fifty to something you can organize a little bit more with other players. It doesn’t mean fifty-vs-fifty is gone (we’re still thinking on how we can iterate on fifty-vs-fifty and make it as good as possible) but there’s no reason not to have fifty-vs-fifty, teams of twenty, and potentially other things like that.

Do you think that’ll effectively change the meta of playing? Do you see a shift in meta when they’re playing in twenty-person teams rather than four-man squads?

Eric Williamson: Certainly, when you have a larger team there are more things that you can do. One of my favorite experiences in fifty-vs-fifty was hearing about someone who decided to be the medic, and all they did was carry around bandages and revive people and not engage in combat—that’s something that’s really cool and doesn’t occur (or is much less likely to occur) in squads. It’s really fun to see that sort of emergent behavior happen.