Sapper

Build 18: the Constructor

Building the driller was one button press once you had the ore. Now it takes a few steps.

The ammo maker is now the Constructor. It still makes ammo, and that's what it does when you build it. Stand on it and press R to pick another recipe: a Frame, an Engine or a Bit, the three parts of a driller. Feed it the ore the part needs, or put a miner beside it, and when the part is done it sits on top until you carry it.

Press 9 for a drill site, then walk each part over to it. You carry one at a time. When the third goes in, the drill starts, and so do its waves. The Bit sets the drill's grade, so deeper down it takes copper, then carbide. A part you carry is safe. A part on the floor isn't: if the swarm wrecks a constructor, its part falls out and the bugs chew it up.

Build 17: they follow you down

Dropping through the hole used to be a clean escape. Not any more. The bugs near you when you drop come down after you, out of the arrival hole a couple of seconds after you land. The more of them were on you, the more follow.

So the first thing to do on a new floor is move: get clear of the hole, then dig in. Your squad shouts when they come.

Build 16: miners come back

Two small fixes from playtesting. A miner that has run out of ore used to just sit there. Now you walk over it and pick it up, and you get its iron back plus anything it was still holding.

And dropping into the hole is quick now: one second instead of four, so the drop feels like a drop.

Build 15: ready for strangers

Sapper goes out as a free web game on November 17, so this build is for people who have never played it. Nothing about the game itself changed: the swarm, the guns and the driller play exactly as in build 14.

The title screen is short now: the name, one line on what it is, and Play, How to play and Settings. The first time you press Play, a five-card guide walks you through moving, digging, a lamp and a turret, the driller and the drop. You can skip it. The tips during play only show the first time too, so a second run isn't nagged.

Settings has music and sound volume, screen shake, tips, and a Low effects mode with half the particles and softer light for slower computers. Space or Esc pauses and shows every key. On a phone you get a card saying it's best on a computer, with a Try anyway button. When a run ends, there's a line to share and a Play again button.

Build 14: light and dark

The cave is dark now, for real. Rock blocks light, and you only see the bugs your light reaches, or the ones right next to you. Every shot flashes, so a firefight lights the walls around it.

Lamps are cheap and light a pocket of cave, but light draws the swarm, so every lamp is a choice. The walls are raised with a dark south face, and ore only glints where it's lit.

You're also the squad's sapper now: the only one who can dig and build. The soldiers are there to keep you alive.

A new name: Sapper

Last Lamp is now called Sapper (Kraig, Nov 4 2026: "sapper is good"). Nothing else changed: build 13 plays the same, and saved runs carry over.

Build 13: a squad with a mind of its own

Playtest notes: the soldiers stuck to me like glue, and digging ore by hand was so fast that miners felt pointless.

Now each squadmate picks a post of its own around you: scouts range out wider, guards keep near your turrets and makers, and anyone who sees a bug within range goes after it. They fall back to you when they're hurt or swarmed, and come back if they wander more than 10 tiles off.

Hand mining is much slower: ore wears down at half the old rate and only about a third of the pieces come out whole. A miner now beats your pick, which is the point: automate early.

Build 12: the Driller

The biggest change yet, straight from playtesting. Before, you could drop to the next floor any time, so rushing down was always the safest move. Now the only way down is the Driller: you build it with what you've mined, and while it bores the swarm hears it and comes in bigger and faster waves until it breaks through. Your squad follows you, guards the drill, and drops with you; anyone who dies stays dead.

Deeper rock is harder, so you need a better drill: Mk I near the surface, Mk II with copper, Mk III with carbide smelted from tungsten found only on floors 4 and 5. Hand mining is slower, so miners matter: they never fill up and you choose what they mine. Your own pistol is weak unless you carry ammo, and the whole curve climbs much harder.

Build 11: a welcome party, then the flood

Playtest notes again: a few bugs are now waiting when you land, you clear them easily, and then there are about 25 seconds of false safety before the flood drops. Surface waves come every 16 seconds and grow each time, and the first push arrives at 2:00.

Space now pauses the game.

Build 10: the surface wakes up sooner

The first real playtest said the surface was too quiet for too long. The waves now start 30 seconds after you land instead of 2 minutes, and the first big push comes at 2:30 instead of 4:00.

Build 9: tuned by bots

Three scripted players (a good one, a careless one and a rusher) played whole runs headless, and the numbers were tuned from what they did: a cap on spitters, egg chambers in the hive, a queen with less health and harder-hitting cannons, a compact build bar.

The good bot reaches the hive on about a third of its runs. No bot has beaten the queen yet.

Build 8: the queen, a map and music

The ending exists: the queen on the last floor, three passes, and a recovery beacon that brings home whoever in the squad is still alive. Then a minimap that only shows what you've seen, and music composed in the browser from one danger number, a key for each floor.

Build 7: allies, spitters and new guns

Other soldiers now hold their own ground on every floor. New bugs: spitters that lob acid from the dark, and borers. New towers: the flamer, the cannon and the arc tower. And the hoard pull: the swarm goes for the biggest pile of value, not always you.

Build 6: Last Lamp

The rename and the first step of the big build: living-dark caves instead of square tiles, the station and the fall, a daylight surface with the squad, borer tunnels that open the way down, six floors, and one life with saves.

Build 5, then the plan for the big build

Build 5 added copper from floor 3 and an ammo maker upgrade.

Then a design pass, written down before any more code: the name Last Lamp, a soldier dropped with a squad to kill the queen, the station and the fall, a daylight surface, six floors that each feel like their own place, and one rule to stop players diving straight down: the way down only opens when the swarm's big push arrives.

Build 4: floors, ore and a flashlight

The cave became a dig: floors you defend until it's too much, then dig down. Iron and crystal with ore pieces, ammo you pick up by walking over it, a miner, a flashlight beam aimed with the mouse, bugs you only see in the light, and swarm sound that tells you direction and size.

The first watched run changed the numbers the same night: slower healing, a cap on bites, a faster ammo maker, and bug remains that pile up in kill zones, slow things down, and rot.

Builds 2 and 3: a build bar, sound, and a recorder

Build 2 added a build bar (1 light, 2 turret, 3 ammo maker), turrets that only shoot bugs in the light, and a first pass on sound and feel, all synthesised in the browser.

Build 3 added a playtest recorder, notes, and a replay viewer, so a session could be watched back instead of guessed at.

Test build 1: one cave and a swarm

The first playable test: one cavern, a swarm that flows like liquid, chewers that eat through rock, turrets, a rumble meter that tells you the swarm is coming, and a way out.

The game was called Underpass then. The question for this build was simple: is holding a cave against a fluid swarm fun at all?