Between the Lanes: Nest of Thorns

Welcome back to Between the Lanes, a blog feature where members of our development team walk through some of the challenges, bugfixes, and occasional happy accidents we encounter while working on a game as unique as Dota.

During an event as massive as Crownfall, we got to try a lot of experiments — overworld maps, branching storylines, hero-themed tokens, minigames, comics, pixel art, and other ideas we’d been eager to explore for years.

What gave us the confidence to take these risks — and something we take constant advantage of at Valve — is the freedom to iterate: to gather real player data, let it challenge our assumptions, and even change our minds. We often say we don’t fully understand what we’re building until we see players interact with it, so we try to get to that point as quickly as possible.

That mindset also shapes when we make decisions — usually as late in development as possible, when we have the best (and sometimes only) data. At every step, we rely on actual player experiences to help us focus on what resonates, and steer away from what doesn't.

In this edition of Between the Lanes, we'll walk through the development of something that came online relatively late in Crownfall — the Act IV boss battle between our heroes and Queen Imperia, Nest of Thorns. We're also using it as a case study to show how playtesting, and the data it generates, shape our decision-making.

Getting to Imperia

The first (and only) minigame in Act I was a modest fishing minigame that had Tidehunter testing your angling skills in the hopes of catching him breakfast. A lot of Act I was like this — small ideas we'd scattered throughout the map to see what players would engage with. The encouraging player data from Act I gave us the confidence to get more adventurous in Act II, and by Act III we were shipping Sleet Fighter, a fighting game brawler at Tusk's favorite dive bar; Dragon Chess, a match-three battle of wits against Winter Wyvern; and Zaug's Lair, a shoot 'em up pitting an evil dragon against Vengeful Spirit through Icewrack's twisting cave system.

By the time we reached Act IV, we had a solid sense of what worked and what didn’t. What kind of data? Everything from the concrete — how many players replayed each minigame, and how often — to the more interpretive, like user-submitted feedback and discussions online. That clarity gave us the confidence to go all-in on a blow-the-doors-off finale: an epic boss battle against the evil Queen Imperia.

Of course, deciding what kind of game the boss battle should be wasn't easy. We knew it needed to deliver the high-stakes spectacle players were expecting. But it also had to offer enough variety and replayability to stay fresh after multiple runs. And because this was a mini-game, designed to be played while queuing for a match, it needed to be intense but brief. It should feel like a tasty snack, not a long meal.

To strike the right balance, we needed a genre that combined the high production values of Sleet Fighter with the replayability of Dragon Chess. After all, this would be the epic showdown between Vengeful Spirit, Skywrath Mage, and newcomer Kez (our "big three" from Crownfall's four-act story) storming Imperia's castle. We wanted the player to feel like they were up against impossible odds in their quest to reach the queen.

Hatching a Plan

One idea that