diff --git a/src/AcDream.Core/Physics/AnimationSequencer.cs b/src/AcDream.Core/Physics/AnimationSequencer.cs
index e65acad..90c8542 100644
--- a/src/AcDream.Core/Physics/AnimationSequencer.cs
+++ b/src/AcDream.Core/Physics/AnimationSequencer.cs
@@ -170,6 +170,10 @@ public sealed class AnimationSequencer
     /// <summary>Current cyclic motion command.</summary>
     public uint CurrentMotion { get; private set; }
 
+    // Diagnostics
+    public int QueueCount => _queue.Count;
+    public bool HasCurrentNode => _currNode != null;
+
     // ── Private state ────────────────────────────────────────────────────────
 
     private readonly Setup _setup;
@@ -379,11 +383,10 @@ public sealed class AnimationSequencer
             else
             {
                 // ── REVERSE PLAYBACK ─────────────────────────────────────
-                // After FUN_005267E0 swaps low↔high for negative speed:
-                //   StartFrame = high (e.g. 3), EndFrame = low (e.g. 0)
-                // GetStartFramePosition placed cursor at (EndFrame+1)-eps ≈ 0.99999.
-                // The cursor counts DOWN toward EndFrame. Boundary = EndFrame.
-                double minBoundary = (double)curr.EndFrame;
+                // No swap: StartFrame is still the LOW value (e.g. 0).
+                // GetStartFramePosition placed cursor at (EndFrame+1)-eps (near high).
+                // The cursor counts DOWN toward StartFrame.
+                double minBoundary = (double)curr.StartFrame;
                 if (newPos <= minBoundary)
                 {
                     // How much time spilled past the lower boundary?
@@ -485,21 +488,13 @@ public sealed class AnimationSequencer
 
         double fr = (double)ad.Framerate * (double)speedMod;
 
-        // ── FUN_005267E0 multiply_framerate ──────────────────────────────
-        // When speed is negative (TurnLeft→TurnRight, SideStepLeft→SideStepRight),
-        // swap Low↔High so the advance loop counts DOWN from the swapped EndFrame
-        // toward the swapped StartFrame.  The pseudocode says:
-        //   if speedScale < 0: swap startFrame ↔ endFrame
-        if (fr < 0.0)
-        {
-            (low, high) = (high, low);
-            // After swap: StartFrame > EndFrame (the loop detects delta < 0 and
-            // uses StartFrame as the lower boundary to count down toward).
-        }
-        else
-        {
-            if (low > high) high = low; // clamp for positive-speed case only
-        }
+        // Do NOT swap StartFrame↔EndFrame for negative speed.
+        // The Advance loop handles negative delta by checking against
+        // StartFrame as the lower boundary. GetStartFramePosition uses
+        // EndFrame (the HIGH value) to start the cursor near the top
+        // for reverse playback, so the cursor traverses all frames
+        // from high→low instead of being stuck in [0,1).
+        if (low > high) high = low;
 
         return new AnimNode(anim, fr, startFrame: low, endFrame: high, isLooping);
     }
diff --git a/tests/AcDream.Core.Tests/Physics/AnimationSequencerTests.cs b/tests/AcDream.Core.Tests/Physics/AnimationSequencerTests.cs
index 09af88d..f582aba 100644
--- a/tests/AcDream.Core.Tests/Physics/AnimationSequencerTests.cs
+++ b/tests/AcDream.Core.Tests/Physics/AnimationSequencerTests.cs
@@ -456,13 +456,12 @@ public sealed class AnimationSequencerTests
         // CurrentMotion should record the original TurnLeft command.
         Assert.Equal(TurnLeft, seq.CurrentMotion);
 
-        // After FUN_005267E0 (multiply_framerate) swaps low↔high for negative speed:
-        //   StartFrame = 3 (was high), EndFrame = 0 (was low)
-        // GetStartFramePosition for negative speed = (EndFrame + 1) - EPSILON = (0+1) - eps ≈ 0.99999.
-        // The cursor starts just below frame 1 and counts DOWN toward EndFrame(=0).
+        // Without swap: StartFrame=0, EndFrame=3 (original range preserved).
+        // GetStartFramePosition for negative speed = (EndFrame+1)-eps = (3+1)-eps ≈ 3.99999.
+        // The cursor starts near the HIGH end and counts DOWN toward StartFrame(=0).
         double pos = GetFramePosition(seq);
-        Assert.True(pos > 0.9 && pos < 1.0,
-            $"Expected framePosition near 0.99999 (reverse start near EndFrame+1) but got {pos}");
+        Assert.True(pos > 3.9 && pos < 4.0,
+            $"Expected framePosition near 3.99999 (reverse start near EndFrame+1) but got {pos}");
     }
 
     [Fact]