diff --git a/osu.Desktop.VisualTests/Tests/TestCasePlayer.cs b/osu.Desktop.VisualTests/Tests/TestCasePlayer.cs
index 11d3da366e..0d32532f09 100644
--- a/osu.Desktop.VisualTests/Tests/TestCasePlayer.cs
+++ b/osu.Desktop.VisualTests/Tests/TestCasePlayer.cs
@@ -6,7 +6,6 @@ using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Screens.Testing;
 using osu.Game.Beatmaps;
-using osu.Game.Beatmaps.Formats;
 using OpenTK;
 using osu.Framework.Graphics.Sprites;
 using osu.Game.Beatmaps.IO;
diff --git a/osu.Game.Modes.Osu/Beatmaps/OsuBeatmapProcessor.cs b/osu.Game.Modes.Osu/Beatmaps/OsuBeatmapProcessor.cs
index 053695cb26..17187323d8 100644
--- a/osu.Game.Modes.Osu/Beatmaps/OsuBeatmapProcessor.cs
+++ b/osu.Game.Modes.Osu/Beatmaps/OsuBeatmapProcessor.cs
@@ -14,9 +14,6 @@ namespace osu.Game.Modes.Osu.Beatmaps
 
         public void PostProcess(Beatmap<OsuHitObject> beatmap)
         {
-            if ((beatmap.ComboColors?.Count ?? 0) == 0)
-                return;
-
             int comboIndex = 0;
             int colourIndex = 0;
 
diff --git a/osu.Game/Beatmaps/Beatmap.cs b/osu.Game/Beatmaps/Beatmap.cs
index 05334b2cd2..6dbd605359 100644
--- a/osu.Game/Beatmaps/Beatmap.cs
+++ b/osu.Game/Beatmaps/Beatmap.cs
@@ -19,7 +19,7 @@ namespace osu.Game.Beatmaps
     {
         public BeatmapInfo BeatmapInfo;
         public List<ControlPoint> ControlPoints;
-        public List<Color4> ComboColors = new List<Color4>
+        public readonly List<Color4> ComboColors = new List<Color4>
         {
             new Color4(17, 136, 170, 255),
             new Color4(102, 136, 0, 255),
diff --git a/osu.Game/Modes/UI/HitRenderer.cs b/osu.Game/Modes/UI/HitRenderer.cs
index 63eefe7e3b..7c7349b929 100644
--- a/osu.Game/Modes/UI/HitRenderer.cs
+++ b/osu.Game/Modes/UI/HitRenderer.cs
@@ -11,6 +11,7 @@ using osu.Game.Modes.Objects.Drawables;
 using osu.Game.Screens.Play;
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Linq;
 
 namespace osu.Game.Modes.UI
@@ -52,6 +53,8 @@ namespace osu.Game.Modes.UI
 
         protected HitRenderer(WorkingBeatmap beatmap)
         {
+            Debug.Assert(beatmap != null, "HitRenderer initialized with a null beatmap.");
+
             // Convert + process the beatmap
             Beatmap = CreateBeatmapConverter().Convert(beatmap.Beatmap);
             Beatmap.HitObjects.ForEach(CreateBeatmapProcessor().SetDefaults);