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diff --git a/src/LivingVillage.Desktop.Tests/P42LaunchFxTests.fs b/src/LivingVillage.Desktop.Tests/P42LaunchFxTests.fs
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+namespace LivingVillage.Desktop.Tests
+
+open Microsoft.VisualStudio.TestTools.UnitTesting
+open LivingVillage.Desktop
+
+/// P42 launch/menu environment FX:
+///  * water ripples whose brightness phase is a pure function of (frame, column, row);
+///  * eave/bank lantern breathing glow through the shared P14 premultiplied-alpha path;
+///  * a deterministic shot table for the LV_P42_SHOT evidence hook.
+/// Every function is frame-driven, so re-rendering the same frame is byte-identical.
+[<TestClass>]
+type P42LaunchFxTests () =
+
+    [<TestMethod>]
+    member _.RippleAndBreathAreDeterministicForTheSameFrame () =
+        for frame in [ 0L; 1L; 17L; 30L; 150L; 4097L ] do
+            for column in [ 0; 1; 7; 39 ] do
+                for rowIndex in [ 0; 1 ] do
+                    Assert.AreEqual<float32>(
+                        TitleScreen.waterRippleBrightness frame column rowIndex,
+                        TitleScreen.waterRippleBrightness frame column rowIndex)
+                    Assert.AreEqual<int>(
+                        TitleScreen.waterRippleLift frame column rowIndex,
+                        TitleScreen.waterRippleLift frame column rowIndex)
+            for index in [ 0; 1; 3 ] do
+                Assert.AreEqual<int>(
+                    TitleScreen.lanternBreathAlpha frame index,
+                    TitleScreen.lanternBreathAlpha frame index)
+
+    [<TestMethod>]
+    member _.RipplePhaseMovesWithTheFrame () =
+        // The same column changes brightness as the frame advances (the ripple travels),
+        // and adjacent columns differ at a fixed frame (the ripple is per-tile).
+        let values = [ 0L .. 24L ] |> List.map (fun f -> TitleScreen.waterRippleBrightness f 5 0)
+        Assert.IsTrue(values |> List.distinct |> List.length > 1, "ripple must move with the frame")
+        let atFrame = [ 0 .. 12 ] |> List.map (fun c -> TitleScreen.waterRippleBrightness 40L c 0)
+        Assert.IsTrue(atFrame |> List.distinct |> List.length > 1, "ripple must vary across columns")
+        // Over a full period it swings both above and below the base brightness.
+        let overPeriod = [ for f in 0L .. 80L -> TitleScreen.waterRippleBrightness f 5 0 ]
+        Assert.IsTrue(overPeriod |> List.exists (fun v -> v > 1.0f) && overPeriod |> List.exists (fun v -> v < 1.0f),
+                      "ripple must swing above and below the base brightness")
+
+    [<TestMethod>]
+    member _.BreathAmplitudeIsBoundedAndVaries () =
+        let samples =
+            [ for frame in 0L .. 120L do
+                  for index in 0 .. 5 do
+                      yield TitleScreen.lanternBreathAlpha frame index ]
+        Assert.IsTrue(samples |> List.forall (fun a -> a >= 40 && a <= 96),
+                      "breath alpha must stay in [40, 96] so it never goes dark or saturates")
+        Assert.IsTrue(samples |> List.distinct |> List.length > 1, "breath must vary with frame/index")
+        // Out-of-step lanterns: two adjacent lights differ at the same frame.
+        Assert.AreNotEqual<int>(TitleScreen.lanternBreathAlpha 50L 0, TitleScreen.lanternBreathAlpha 50L 1)
+
+    [<TestMethod>]
+    member _.P42ShotTableIsOrderedAndNamesAreDistinct () =
+        Assert.IsTrue(P42ShotScript.splashEarlyFrame < P42ShotScript.splashLateFrame)
+        Assert.IsTrue(LaunchScreen.revealProgress P42ShotScript.splashEarlyFrame > 0.0f)
+        Assert.IsTrue(LaunchScreen.revealProgress P42ShotScript.splashLateFrame < 1.0f,
+                      "both splash FX frames must still show the water band")
+        Assert.IsTrue(P42ShotScript.menuFrame >= 120L, "menu shot must wait for the entrance to settle")
+        let names = [ P42ShotScript.splashEarlyName; P42ShotScript.splashLateName; P42ShotScript.menuName ]
+        Assert.AreEqual<int>(names.Length, names |> List.distinct |> List.length)
+
+    [<TestMethod>]
+    member _.RippleAmplitudeStaysAboveVisibilityBudget () =
+        // Guards against a regression that quietly lowers the ripple back below visibility.
+        Assert.IsTrue(TitleScreen.waterRippleAmplitude >= 0.25f,
+                      "ripple amplitude must stay >= 0.25 to read at 1280x720 (1x)")
+        let samples =
+            [ for frame in 0L .. 40L do
+                  for column in 0 .. 39 do
+                      yield TitleScreen.waterRippleBrightness frame column 0 ]
+        let peakToPeak = (List.max samples) - (List.min samples)
+        Assert.IsTrue(peakToPeak >= 0.5f, sprintf "ripple peak-to-peak %.3f must be >= 0.50" peakToPeak)
+        // Adjacent 28px tile columns must differ enough to be visible at 1x.
+        let brightness = TitleScreen.waterRippleBrightness 150L
+        let adjacent = [ for column in 0 .. 38 -> abs (brightness column 0 - brightness (column + 1) 0) ]
+        Assert.IsTrue(List.max adjacent >= 0.2f, sprintf "max adjacent-column ripple step %.3f must be >= 0.20" (List.max adjacent))