Slonge Games

Why every Bonestorm run lasts seven minutes

4 min readBy Slonge Games

Bonestorm Survivors gameplay: a skeleton horde closing in on the hero in the Moonlit Graveyard.

Ask anyone who plays survivors-likes on a phone how long a run should be and you get two answers at once: "long enough to build something" and "short enough to finish before my stop". For Bonestorm Survivors we settled on seven minutes. This post is about how we got there and what had to change to make those seven minutes feel full.

Five minutes was too short

The first playable version of the game ran for five minutes and ended with a single boss at 4:00. It was tight and it worked, but our own notes from the time are blunt: about 17 level-ups is not enough room for weapon evolutions, points of interest and a boss to all matter in one run. One boss also gave the run only one climax.

We compared three options: keep five minutes, go to seven with two bosses, or go to the genre's usual ten minutes and more. Ten was too long for the amount of content we had and for a phone session. Seven won.

The shape of a run

Every world uses the same run structure:

  • 0:00 to 3:00: the horde builds up. Spawns speed up in steps, the first elites appear, and a ring of skeletons closes in around 1:15.
  • 3:00: the mid-boss. While a boss is alive, normal spawns drop to half rate, so the fight is about the boss, not about drowning.
  • 3:30 to 6:00: the hard middle. Rings, sweeping swarms and elites with modifiers arrive faster, and enemy health climbs steeply.
  • 6:00: the final boss. The music changes for each act, so you can hear where you are without looking at the timer.
  • 7:00: if the boss is still standing, it enrages, and the fight gets much harder fast.

In our automated test runs (a simple bot playing the Knight with a mid-level save), Normal wins land between about 6:15 and 7:20. That is the target: most of the time the boss falls in the last minute, and occasionally you are fighting the enraged version with your back to the wall.

Bonestorm Survivors level-up screen offering three upgrade cards: Knight's Blade, Ricochet Saws and Frozen Heart.
Every level-up offers three cards. Over seven minutes that adds up to a real build.

"No more upgrades at 4:00"

The most useful feedback we got in testing was one sentence: "I got two 5x chests and hit no more upgrades at 4:00." A lucky run had maxed every weapon and passive by the middle of the run, and from then on every level-up was a pile of gold instead of a choice.

The fix had two parts. First, evolving a weapon became a choice: once a weapon reaches level 5 and you hold its matching relic, an evolution card shows up among your normal level-up cards. You can take it right away, or keep levelling the base weapon to level 8 first, and that extra damage carries into the evolution.

Second, evolved weapons got their own track, Evo Lv1 to Lv8. Each step adds damage or improves one of the things that evolution actually uses, such as area, cooldown, duration or projectile count. A maxed evolution ends up roughly twice as strong as a fresh one, and three to four times a maxed base weapon.

We tested the worst case on purpose: a bot run with extra cursed difficulty from the start and two royal five-item chests forced in around 2:30 and 3:30. With the old rules that run ran out of upgrades at about 5:07. With the new rules it never ran out; the pool was empty only at the moment of victory.

Bonestorm Survivors gameplay: four evolved weapons firing at once through a skeleton horde.
Four evolutions at once. There are 20 in the game, and each one has its own Evo Lv1 to Lv8 track.

Normal, Hard and Nightmare

The seven worlds share the same clock, so on their own they are more of a reward ladder than a difficulty ladder: later worlds have a little more enemy health and pay a lot more gold. The real difficulty axis is the tier you pick for each world.

  • Hard unlocks when you win a world on Normal. Enemies have 1.8 times the health and spawn 1.35 times as fast, hits hurt 20 % more, and you earn 1.5 times the gold.
  • Nightmare unlocks when you win Hard. Enemy health is 2.6 times, spawns 1.6 times as fast, hits 40 % harder, elites get an extra modifier, and gold is 2.2 times.

Two details matter a lot on a phone. The extra health and spawn speed ramp in over the first two and a half minutes, because at full strength from the first second Nightmare killed starter builds before any weapon came online. And we kept damage moderate: one-shot deaths feel unfair when you are steering with one thumb, so health and crowd density do most of the work.

Something sleeps below

On Hard and Nightmare, every world hides one more fight. We are not going to spoil how to wake it. The game drops a hint when you win on Hard, and the Codex has seven entries marked "???" waiting to be filled in. One promise: if you find it and it beats you, you still keep your victory.

Play a run

Bonestorm Survivors is in closed beta on iPhone and Android. If you want to see whether seven minutes feels right to you, join the beta, and tell us when you ran out of upgrades, if you ever do.