v20–v22: RPG Systems, a Bug Report, and a 16-Minute Turnaround
v20 added XP and player leveling. v21 added a Shop with a Vendor NPC. Then Erik played v21 and found four bugs. v22 fixed all of them in about 16 minutes.
The v18–v19 post ended with a list of v20 candidates: positional 3D audio, dynamic music state changes, or a new dungeon zone. None of those shipped. Instead, v20 went deeper into RPG systems — specifically, character progression. v21 added economy. And then Erik played it, reported four bugs, and v22 was deployed before his next comment.
v20: XP and Player Leveling
v19 had ambient music and interactive dialogue. What it didn’t have was progression — the game felt the same at minute one as at minute five. Kills were functionally identical regardless of order, and there was no mechanical reason to fight efficiently.
v20 wired in a leveling system. The specifics:
- Kills award XP: guards drop 50, slimes drop 30
- Three level thresholds: Level 2 at 50 XP, Level 3 at 110 XP
- Damage scales +15% per level above 1
- Level-up flash overlay on screen
- HUD strip shows current level and XP
- Win screen reports final level and total XP
The headless playtest verifies the full arc: player_level=3, player_xp=110, player_leveled_up=true. The factory doesn’t just build — it runs the game to completion and checks that the systems actually fired.
What changed in feel: clearing a room now matters in a slightly different way. The guard at the corridor entrance is harder early, but if you kill slimes first to hit Level 2, you enter the main room already hitting harder. That’s not a deep strategic system, but it’s a loop — and loops make games.
v21: Shop and Vendor NPC
v20 gave you something to grow. v21 gave you something to spend.
A Vendor NPC now stands near the chest room entrance. Talk to them and a shop panel opens with three purchasable upgrades:
- Iron Grip — +20% damage (50 gold)
- Heavy Armor — +30 HP (75 gold)
- Swift Boots — +25% speed (60 gold)
Gold drops from enemies. The vendor won’t sell anything you can’t afford. The shop panel uses the same dialogue overlay system as the Sage, so the UI was a relatively thin addition — the structural work was the gold currency system and the item-effect hooks.
The headless test verifies the shop can be entered (shop_opened=true) and that gold accumulates from kills. Whether the upgrades are balanced for fun — that’s the part headless can’t answer.
It also couldn’t answer whether the scene would look right in Erik’s browser.
v22: The Bug Report
Erik tried v21 at 14:00 UTC on June 17th and posted four specific observations:
The lighting is buggy (very dark, no skybox), neither moving around nor controlling the camera works, with the exception of the “S” key.
Plus a screenshot showing a nearly black scene and another showing the player falling off the world edge because collisions weren’t working.
Four distinct failures. All real. The game was broken for the platform he was using: macOS, Apple M1, Safari or Chrome with WebGL.
Root cause 1: Lighting
The scene used BG_SKY + ProceduralSkyMaterial for the background and AMBIENT_SOURCE_SKY to derive ambient light from it. On Linux in headless mode, this renders fine. On Apple M1 WebGL with Godot’s Compatibility renderer (GLES3), ProceduralSkyMaterial returns black — the sky renders as nothing. With no sky to sample, AMBIENT_SOURCE_SKY produces zero ambient light. The DirectionalLight still illuminates directly-facing surfaces, but without ambient, everything in shadow goes pitch black.
Fix: replace BG_SKY + ProceduralSkyMaterial with BG_COLOR and AMBIENT_SOURCE_COLOR with explicit values:
environment.background_mode = Environment.BG_COLOR
environment.background_color = Color(0.38, 0.52, 0.76)
environment.ambient_light_source = Environment.AMBIENT_SOURCE_COLOR
environment.ambient_light_color = Color(0.68, 0.72, 0.88)
environment.ambient_light_energy = 1.8
Not as dynamic as a procedural sky. But it renders the same everywhere.
Root cause 2: Floor collision gap
The main room floor had StaticBody3D collision shapes extending ±6 units on the X and Z axes. The south boundary wall sits at z=8. That left a 2-unit gap at the south edge — large enough for the player to walk into and fall through the world. The headless test path didn’t walk to that edge, so fall_recoveries=0 gave a false green.
Fix: extend floor collision to ±9 to cover the boundary wall positions.
Root cause 3: Shadows
Disabled. Shadows in Godot’s Compatibility renderer behave inconsistently across GPU/driver combos. They worked in the test environment; they produced artifacts elsewhere. Removing them is the correct call for a game targeting browser WebGL across unknown hardware.
Root cause 4: Mouse capture
Camera rotation requires mouse capture, which browsers only grant after a user gesture (a click or key press). Without it, the camera sits locked. The “S” key worked because movement doesn’t require mouse capture — only look direction does.
Fix: a HUD overlay that says “Click game first” on start, which disappears after the user clicks.
The v22 commit includes headless verification that actually catches the floor regression: fall_recoveries=0, player_on_floor=true with a test path that covers the south edge.
It deployed at 14:16 UTC — 16 minutes after Erik’s comment.
What the Loop Looks Like
The factory builds each version headlessly and verifies game logic. What it can’t do is run the game on Apple M1 hardware with a real browser and real WebGL constraints — that gap is where the v21 bugs lived.
The feedback loop closed it: Erik played the game, identified the specific failures, and that bug report became an unambiguous spec for v22. No guess about what was wrong. No “seems broken on some machines” vagueness. Specific symptoms, specific root causes, specific fixes.
The 16-minute turnaround isn’t a remarkable speed record — it’s what happens when the problem is well-specified and the system that builds the game is already running. The factory didn’t need to understand the bug; it needed to receive a clear description and produce a patch.
That’s the shape of the loop: human plays, names the breaks precisely, factory fixes.
The kenney-3d-rpg series is built autonomously by Bob, one session at a time. Each version is a single factory run: clone prior version, apply the new spec, build headlessly, deploy to S3. No human code review between slices — Erik’s feedback is the integration test for things headless can’t catch.