diff --git a/indigo/build.sbt b/indigo/build.sbt
index 0f3621c59..bbe8d16a8 100644
--- a/indigo/build.sbt
+++ b/indigo/build.sbt
@@ -131,11 +131,11 @@ lazy val sandbox =
           .embedFont(
             "TestFont",
             os.pwd / "sandbox" / "assets" / "fonts" / "pixelated.ttf",
-              FontOptions(
-                "test font",
-                32,
-                CharSet.fromUniqueString("The quick brown fox\njumps over the\nlazy dog.")
-              )
+            FontOptions(
+              "test font",
+              32,
+              CharSet.fromUniqueString("The quick brown fox\njumps over the\nlazy dog.")
+            )
               .withColor(RGB.White)
               .withMaxCharactersPerLine(16)
               .noAntiAliasing,
@@ -275,13 +275,11 @@ lazy val jsdocs = project
     organization := "io.indigoengine",
     libraryDependencies ++= Dependencies.jsDocs.value,
     libraryDependencies ++= Seq(
-      "io.indigoengine" %%% "indigo-json-circe" % indigoDocsVersion,
-      "io.indigoengine" %%% "indigo"            % indigoDocsVersion,
-      "io.indigoengine" %%% "indigo-extras"     % indigoDocsVersion,
-      // TODO: After next release (>0.15.2), should be Dependencies.Versions.tyrianVersion
-      "io.indigoengine" %%% "tyrian-io" % tyrianDocsVersion,
-      // TODO: After next release (>0.15.2), should be indigoDocsVersion
-      "io.indigoengine" %%% "tyrian-indigo-bridge" % tyrianDocsVersion
+      "io.indigoengine" %%% "indigo-json-circe"    % indigoDocsVersion,
+      "io.indigoengine" %%% "indigo"               % indigoDocsVersion,
+      "io.indigoengine" %%% "indigo-extras"        % indigoDocsVersion,
+      "io.indigoengine" %%% "tyrian-io"            % tyrianDocsVersion,
+      "io.indigoengine" %%% "tyrian-indigo-bridge" % indigoDocsVersion
     ),
     Compile / tpolecatExcludeOptions ++= Set(
       ScalacOptions.warnValueDiscard,
diff --git a/indigo/docs/01-quickstart/hello-indigo.md b/indigo/docs/01-quickstart/hello-indigo.md
index 10dae5912..9b7455447 100644
--- a/indigo/docs/01-quickstart/hello-indigo.md
+++ b/indigo/docs/01-quickstart/hello-indigo.md
@@ -435,7 +435,7 @@ val model = Model.initial(Point.zero)
 def drawDots(
     center: Point,
     dots: Batch[Dot]
-): Batch[Graphic[_]] =
+): Batch[Graphic[?]] =
   dots.map { dot =>
     val position = Point(
       x = (Math.sin(dot.angle.toDouble) * dot.orbitDistance + center.x).toInt,
diff --git a/indigo/docs/02-guides/howto-custom-entity.md b/indigo/docs/02-guides/howto-custom-entity.md
index 90da4d895..2b285252b 100644
--- a/indigo/docs/02-guides/howto-custom-entity.md
+++ b/indigo/docs/02-guides/howto-custom-entity.md
@@ -122,7 +122,7 @@ First, tell indigo about the new shader:
 In the sandbox this would be a game field just like assets and fonts, i.e. `val shaders: Set[Shader] = Set(MyColoredEntity.shader)`, and there is an equivalent for the `BootResult` type as follows:
 
 ```scala mdoc:js
-def boot(flags: Map[String, String]): Outcome[BootResult[Unit]] =
+def boot(flags: Map[String, String]): Outcome[BootResult[Unit, Unit]] =
   Outcome(
     BootResult
       .noData(GameConfig.default)
diff --git a/indigo/docs/03-gameloop/outcome.md b/indigo/docs/03-gameloop/outcome.md
index 4453a81a0..8d7f09fd8 100644
--- a/indigo/docs/03-gameloop/outcome.md
+++ b/indigo/docs/03-gameloop/outcome.md
@@ -51,7 +51,7 @@ Outcome(10).map(_ * 20)                    // Outcome(200)
 Outcome(10).ap(Outcome((i: Int) => i * 5)) // Outcome(50)
 Outcome(10).flatMap(i => Outcome(i * 20))  // Outcome(200)
 Outcome(10).merge(Outcome(20))(_ + _)      // Outcome(30)
-Outcome("a") combine Outcome("b")          // Outcome(("a", "b"))
+Outcome("a") `combine` Outcome("b")          // Outcome(("a", "b"))
 ```
 
 As mentioned, `Outcome`'s map function is bias towards the state, but you can also modify the events with `mapGlobalEvents`.
diff --git a/indigo/docs/04-organisation/boot-and-start-up.md b/indigo/docs/04-organisation/boot-and-start-up.md
index ec33ed045..e5dc701d3 100644
--- a/indigo/docs/04-organisation/boot-and-start-up.md
+++ b/indigo/docs/04-organisation/boot-and-start-up.md
@@ -28,7 +28,7 @@ import indigo.*
 
 final case class BootData(myData: String)
 
-def boot(flags: Map[String, String]): Outcome[BootResult[BootData]] = ???
+def boot(flags: Map[String, String]): Outcome[BootResult[BootData, Unit]] = ???
 ```
 
 #### Flags
@@ -46,7 +46,7 @@ Well we use a flag, like this:
 ```scala mdoc:js
 import indigo.*
 
-def boot(flags: Map[String, String]): Outcome[BootResult[GameViewport]] = {
+def boot(flags: Map[String, String]): Outcome[BootResult[GameViewport, Unit]] = {
   val assetPath: String =
     flags.getOrElse("baseUrl", "")
 
diff --git a/indigo/docs/04-organisation/scene-management.md b/indigo/docs/04-organisation/scene-management.md
index 688b6a18c..4326d69ec 100644
--- a/indigo/docs/04-organisation/scene-management.md
+++ b/indigo/docs/04-organisation/scene-management.md
@@ -65,7 +65,7 @@ trait Scene[StartUpData, GameModel, ViewModel] derives CanEqual {
   def modelLens: Lens[GameModel, SceneModel]
   def viewModelLens: Lens[ViewModel, SceneViewModel]
   def eventFilters: EventFilters
-  def subSystems: Set[SubSystem]
+  def subSystems: Set[SubSystem[GameModel]]
 
   def updateModel(context: SceneContext[StartUpData], model: SceneModel): GlobalEvent => Outcome[SceneModel]
   def updateViewModel(context: SceneContext[StartUpData], model: SceneModel, viewModel: SceneViewModel): GlobalEvent => Outcome[SceneViewModel]
@@ -164,7 +164,7 @@ object LevelScene extends Scene[Unit, DungeonGameModel, Unit]:
   def modelLens: Lens[DungeonGameModel, LevelModel] = Lens(_.level, (m, lvl) => m.copy(level = lvl))
   def viewModelLens: Lens[Unit, Unit] = Lens.unit
   def name: SceneName = SceneName("level")
-  def subSystems: Set[SubSystem] = Set()
+  def subSystems: Set[SubSystem[DungeonGameModel]] = Set()
 
   def updateModel(context: SceneContext[Unit], model: LevelModel): GlobalEvent => Outcome[LevelModel] =
     _ => Outcome(model.copy(health = model.health + 1)) // On any event, increase health!
@@ -228,7 +228,7 @@ val inventory     = Inventory(Weapons(Sword(1)))
 val betterSword   = Sword(2)
 
 val mySwordLens = 
-  inventoryLens andThen weaponsLens // Composing lenses!
+  inventoryLens `andThen` weaponsLens // Composing lenses!
 
 mySwordLens.get(inventory) // a sword
 mySwordLens.set(inventory, betterSword) // an inventory with a better sword in it
diff --git a/indigo/docs/04-organisation/subsystems.md b/indigo/docs/04-organisation/subsystems.md
index 790d3d87c..161ecded6 100644
--- a/indigo/docs/04-organisation/subsystems.md
+++ b/indigo/docs/04-organisation/subsystems.md
@@ -16,9 +16,10 @@ As an example, consider this simple (and arguably unhelpful) subsystem that trac
 ```scala mdoc:js
 import indigo.*
 
-final case class PointsTrackerExample(startingPoints: Int) extends SubSystem:
+final case class PointsTrackerExample(startingPoints: Int) extends SubSystem[Unit]:
   type EventType      = PointsTrackerEvent
   type SubSystemModel = Int
+  type ReferenceData  = Unit
 
   val id: SubSystemId = SubSystemId("points tracker")
 
@@ -27,10 +28,12 @@ final case class PointsTrackerExample(startingPoints: Int) extends SubSystem:
     case _                                => None
   }
 
+  def reference(model: Unit): Unit = ()
+
   def initialModel: Outcome[Int] =
     Outcome(startingPoints)
 
-  def update(context: SubSystemFrameContext, points: Int): PointsTrackerEvent => Outcome[Int] = {
+  def update(context: SubSystemFrameContext[Unit], points: Int): PointsTrackerEvent => Outcome[Int] = {
     case PointsTrackerEvent.Add(pts) =>
       Outcome(points + pts)
 
@@ -39,7 +42,7 @@ final case class PointsTrackerExample(startingPoints: Int) extends SubSystem:
         .addGlobalEvents(GameOver)
   }
 
-  def present(context: SubSystemFrameContext, points: Int): Outcome[SceneUpdateFragment] =
+  def present(context: SubSystemFrameContext[Unit], points: Int): Outcome[SceneUpdateFragment] =
     Outcome(
       SceneUpdateFragment(Text(points.toString, FontKey(""), Material.Bitmap(AssetName("font"))))
     )
diff --git a/indigo/docs/05-platform/assets.md b/indigo/docs/05-platform/assets.md
index e35352b90..4e1a746fc 100644
--- a/indigo/docs/05-platform/assets.md
+++ b/indigo/docs/05-platform/assets.md
@@ -64,7 +64,7 @@ val assets: Set[AssetType] =
   )
 
 // Or if you're using the IndigoDemo` or `IndigoGame` entry points
-def boot(flags: Map[String, String]): BootResult[Unit] =
+def boot(flags: Map[String, String]): BootResult[Unit, Unit] =
   BootResult.noData(GameConfig.default)
     .withAssets(
       Set(
diff --git a/indigo/docs/06-presentation/cameras.md b/indigo/docs/06-presentation/cameras.md
index 5535a5f5e..8aa0462a1 100644
--- a/indigo/docs/06-presentation/cameras.md
+++ b/indigo/docs/06-presentation/cameras.md
@@ -43,7 +43,7 @@ Camera.LookAt(Point(10, 10), Zoom.x2, Radians.fromDegrees(45))
 Cameras can be optionally added to your `SceneUpdateFragment`s or `Layer`s, e.g.:
 
 ```scala mdoc:js
-Layer(BindingKey("my layer"))
+Layer.empty
   .withCamera(Camera.LookAt(Point(10, 10), Zoom.x2, Radians.fromDegrees(45)))
 ```
 
@@ -72,8 +72,8 @@ val sceneB = SceneUpdateFragment.empty.withCamera(Camera.LookAt(Point(20, 20)))
 ..where as here, the camera in `layerA` looking at position `Point(10, 10)` is selected.
 
 ```scala mdoc:js
-val layerA = Layer(BindingKey("Layer A")).withCamera(Camera.LookAt(Point(10, 10)))
-val layerB = Layer(BindingKey("Layer B")).withCamera(Camera.LookAt(Point(20, 20)))
+val layerA = Layer.empty.withCamera(Camera.LookAt(Point(10, 10)))
+val layerB = Layer.empty.withCamera(Camera.LookAt(Point(20, 20)))
 ```
 
 ```scala
diff --git a/indigo/docs/06-presentation/layers.md b/indigo/docs/06-presentation/layers.md
index 103952d31..33beef0b8 100644
--- a/indigo/docs/06-presentation/layers.md
+++ b/indigo/docs/06-presentation/layers.md
@@ -70,10 +70,10 @@ However, you may want to merge scenes and have all the elements end up on the sa
 
 ```scala mdoc:js
 val c = SceneUpdateFragment(
-  Layer(BindingKey("my layer"), graphicA, graphicA, graphicA)
+  BindingKey("my layer") -> Layer(graphicA, graphicA, graphicA)
 )
 val d = SceneUpdateFragment(
-  Layer(BindingKey("my layer"), graphicB, graphicB, graphicB)
+  BindingKey("my layer") -> Layer(graphicB, graphicB, graphicB)
 )
 
 c |+| d
@@ -83,10 +83,10 @@ Results in:
 
 ```scala mdoc:js
 SceneUpdateFragment(
-  Layer(
-    BindingKey("my layer"),
-    Batch(graphicA, graphicA, graphicA, graphicB, graphicB, graphicB)
-  )
+  BindingKey("my layer") ->
+    Layer.Content(
+      Batch(graphicA, graphicA, graphicA, graphicB, graphicB, graphicB)
+    )
 )
 ```
 
diff --git a/indigo/docs/06-presentation/lighting.md b/indigo/docs/06-presentation/lighting.md
index a42d25e1a..8ec0e9b1c 100644
--- a/indigo/docs/06-presentation/lighting.md
+++ b/indigo/docs/06-presentation/lighting.md
@@ -49,7 +49,7 @@ Dynamic lighting changes the scene's lighting as the light moves around. It high
 
 ```scala mdoc:js
 SceneUpdateFragment(
-  Layer(BindingKey("my layer")).withLights(PointLight(Point(100, 100), RGBA.Green))
+  Layer.empty.withLights(PointLight(Point(100, 100), RGBA.Green))
 ).withLights(AmbientLight(RGBA.Blue.withAlpha(0.2)))
 ```
 
diff --git a/indigo/docs/06-presentation/scene-update-fragment.md b/indigo/docs/06-presentation/scene-update-fragment.md
index 8d113b178..92bbc43b3 100644
--- a/indigo/docs/06-presentation/scene-update-fragment.md
+++ b/indigo/docs/06-presentation/scene-update-fragment.md
@@ -12,7 +12,7 @@ val graphic =
     .withLighting(LightingModel.Lit.flat))
 
 SceneUpdateFragment(
-    Layer(BindingKey("game layer"), graphic)
+    BindingKey("game layer") -> Layer(graphic)
   )
   .withLights(
     AmbientLight(RGBA.White.withAmount(0.25)),