diff --git a/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/Data/MonoEncoding.cs b/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/Data/MonoEncoding.cs
index 7eee8896ac..0e998696f9 100644
--- a/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/Data/MonoEncoding.cs
+++ b/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/Data/MonoEncoding.cs
@@ -15,7 +15,6 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour.Data
     {
         /// <summary>
         /// List of <see cref="DifficultyHitObject"/>s that are encoded within this <see cref="MonoEncoding"/>.
-        /// This is not declared as <see cref="TaikoDifficultyHitObject"/> to avoid circular dependencies.
         /// </summary>
         public List<TaikoDifficultyHitObject> EncodedData { get; private set; } = new List<TaikoDifficultyHitObject>();
 
diff --git a/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/TaikoColourDifficultyPreprocessor.cs b/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/TaikoColourDifficultyPreprocessor.cs
index 517e240682..7b7fab26b1 100644
--- a/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/TaikoColourDifficultyPreprocessor.cs
+++ b/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/TaikoColourDifficultyPreprocessor.cs
@@ -9,8 +9,7 @@ using osu.Game.Rulesets.Taiko.Objects;
 namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour
 {
     /// <summary>
-    /// Utility class to perform various encodings. This is separated out from the encoding classes to prevent circular
-    /// dependencies.
+    /// Utility class to perform various encodings.
     /// </summary>
     public class TaikoColourDifficultyPreprocessor
     {
@@ -26,7 +25,7 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour
 
             // Assign indexing and encoding data to all relevant objects. Only the first note of each encoding type is
             // assigned with the relevant encodings.
-            encodings.ForEach(coupledEncoding =>
+            foreach (var coupledEncoding in encodings)
             {
                 coupledEncoding.Payload[0].Payload[0].EncodedData[0].Colour.CoupledColourEncoding = coupledEncoding;
 
@@ -48,7 +47,7 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour
                         monoEncoding.EncodedData[0].Colour.MonoEncoding = monoEncoding;
                     }
                 }
-            });
+            }
 
             return colours;
         }
@@ -58,35 +57,29 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour
         /// </summary>
         public static List<MonoEncoding> EncodeMono(List<DifficultyHitObject> data)
         {
-            List<MonoEncoding> encoded = new List<MonoEncoding>();
-
-            MonoEncoding? lastEncoded = null;
+            List<MonoEncoding> encodings = new List<MonoEncoding>();
+            MonoEncoding? currentEncoding = null;
 
             for (int i = 0; i < data.Count; i++)
             {
                 TaikoDifficultyHitObject taikoObject = (TaikoDifficultyHitObject)data[i];
+
                 // This ignores all non-note objects, which may or may not be the desired behaviour
                 TaikoDifficultyHitObject? previousObject = taikoObject.PreviousNote(0);
 
-                // If the colour changed or if this is the first object in the run, create a new mono encoding
-                if
-                (
-                    previousObject == null || // First object in the list
-                    (taikoObject.BaseObject as Hit)?.Type != (previousObject.BaseObject as Hit)?.Type
-                )
+                // If this is the first object in the list or the colour changed, create a new mono encoding
+                if (currentEncoding == null || (taikoObject.BaseObject as Hit)?.Type != (previousObject?.BaseObject as Hit)?.Type)
                 {
-                    lastEncoded = new MonoEncoding();
-                    lastEncoded.EncodedData.Add(taikoObject);
-                    encoded.Add(lastEncoded);
+                    currentEncoding = new MonoEncoding();
+                    encodings.Add(currentEncoding);
                     continue;
                 }
 
-                // If we're here, we're in the same encoding as the previous object, thus lastEncoded is not null.
                 // Add the current object to the encoded payload.
-                lastEncoded!.EncodedData.Add(taikoObject);
+                currentEncoding.EncodedData.Add(taikoObject);
             }
 
-            return encoded;
+            return encodings;
         }
 
         /// <summary>
@@ -94,27 +87,24 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour
         /// </summary>
         public static List<ColourEncoding> EncodeColour(List<MonoEncoding> data)
         {
-            List<ColourEncoding> encoded = new List<ColourEncoding>();
-            ColourEncoding? lastEncoded = null;
+            List<ColourEncoding> encodings = new List<ColourEncoding>();
+            ColourEncoding? currentEncoding = null;
 
             for (int i = 0; i < data.Count; i++)
             {
-                // Starts a new ColourEncoding if the previous MonoEncoding has a different mono length, or if this is
-                // the first MonoEncoding in the list.
-                if (lastEncoded == null || data[i].RunLength != data[i - 1].RunLength)
+                // Start a new ColourEncoding if the previous MonoEncoding has a different mono length, or if this is the first MonoEncoding in the list.
+                if (currentEncoding == null || data[i].RunLength != data[i - 1].RunLength)
                 {
-                    lastEncoded = new ColourEncoding();
-                    lastEncoded.Payload.Add(data[i]);
-                    encoded.Add(lastEncoded);
+                    currentEncoding = new ColourEncoding();
+                    encodings.Add(currentEncoding);
                     continue;
                 }
 
-                // If we're here, we're in the same encoding as the previous object. Add the current MonoEncoding to the
-                // encoded payload.
-                lastEncoded.Payload.Add(data[i]);
+                // Add the current MonoEncoding to the encoded payload.
+                currentEncoding.Payload.Add(data[i]);
             }
 
-            return encoded;
+            return encodings;
         }
 
         /// <summary>
@@ -122,16 +112,15 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour
         /// </summary>
         public static List<CoupledColourEncoding> EncodeCoupledColour(List<ColourEncoding> data)
         {
-            List<CoupledColourEncoding> encoded = new List<CoupledColourEncoding>();
-            CoupledColourEncoding? lastEncoded = null;
+            List<CoupledColourEncoding> encodings = new List<CoupledColourEncoding>();
+            CoupledColourEncoding? currentEncoding = null;
 
             for (int i = 0; i < data.Count; i++)
             {
-                // Starts a new CoupledColourEncoding. ColourEncodings that should be grouped together will be handled
-                // later within this loop.
-                lastEncoded = new CoupledColourEncoding
+                // Start a new CoupledColourEncoding. ColourEncodings that should be grouped together will be handled later within this loop.
+                currentEncoding = new CoupledColourEncoding
                 {
-                    Previous = lastEncoded
+                    Previous = currentEncoding
                 };
 
                 // Determine if future ColourEncodings should be grouped.
@@ -140,7 +129,7 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour
                 if (!isCoupled)
                 {
                     // If not, add the current ColourEncoding to the encoded payload and continue.
-                    lastEncoded.Payload.Add(data[i]);
+                    currentEncoding.Payload.Add(data[i]);
                 }
                 else
                 {
@@ -148,27 +137,27 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour
                     // subsequent ColourEncodings should be grouped by increasing i and doing the appropriate isCoupled check.
                     while (isCoupled)
                     {
-                        lastEncoded.Payload.Add(data[i]);
+                        currentEncoding.Payload.Add(data[i]);
                         i++;
                         isCoupled = i < data.Count - 2 && data[i].IsRepetitionOf(data[i + 2]);
                     }
 
                     // Skip over viewed data and add the rest to the payload
-                    lastEncoded.Payload.Add(data[i]);
-                    lastEncoded.Payload.Add(data[i + 1]);
+                    currentEncoding.Payload.Add(data[i]);
+                    currentEncoding.Payload.Add(data[i + 1]);
                     i++;
                 }
 
-                encoded.Add(lastEncoded);
+                encodings.Add(currentEncoding);
             }
 
             // Final pass to find repetition intervals
-            for (int i = 0; i < encoded.Count; i++)
+            for (int i = 0; i < encodings.Count; i++)
             {
-                encoded[i].FindRepetitionInterval();
+                encodings[i].FindRepetitionInterval();
             }
 
-            return encoded;
+            return encodings;
         }
 
         /// <summary>
diff --git a/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/TaikoDifficultyHitObjectColour.cs b/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/TaikoDifficultyHitObjectColour.cs
index 6a6b427393..41080eeb33 100644
--- a/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/TaikoDifficultyHitObjectColour.cs
+++ b/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/TaikoDifficultyHitObjectColour.cs
@@ -11,20 +11,17 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour
     public class TaikoDifficultyHitObjectColour
     {
         /// <summary>
-        /// <see cref="MonoEncoding"/> encoding that encodes this note, only present if this is the first note within a
-        /// <see cref="MonoEncoding"/>
+        /// The <see cref="MonoEncoding"/> that encodes this note, only present if this is the first note within a <see cref="MonoEncoding"/>
         /// </summary>
         public MonoEncoding? MonoEncoding;
 
         /// <summary>
-        /// <see cref="ColourEncoding"/> encoding that encodes this note, only present if this is the first note within
-        /// a <see cref="ColourEncoding"/>
+        /// The <see cref="ColourEncoding"/> that encodes this note, only present if this is the first note within a <see cref="ColourEncoding"/>
         /// </summary>
         public ColourEncoding? ColourEncoding;
 
         /// <summary>
-        /// <see cref="CoupledColourEncoding"/> encoding that encodes this note, only present if this is the first note
-        /// within a <see cref="CoupledColourEncoding"/>
+        /// The <see cref="CoupledColourEncoding"/> that encodes this note, only present if this is the first note within a <see cref="CoupledColourEncoding"/>
         /// </summary>
         public CoupledColourEncoding? CoupledColourEncoding;
     }
diff --git a/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/TaikoDifficultyHitObject.cs b/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/TaikoDifficultyHitObject.cs
index fd9a225f6a..e7a8abfd38 100644
--- a/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/TaikoDifficultyHitObject.cs
+++ b/osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/TaikoDifficultyHitObject.cs
@@ -45,9 +45,8 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing
         /// <summary>
         /// Colour data for this hit object. This is used by colour evaluator to calculate colour difficulty, but can be used
         /// by other skills in the future.
-        /// This need to be writeable by TaikoDifficultyHitObjectColour so that it can assign potentially reused instances
         /// </summary>
-        public TaikoDifficultyHitObjectColour Colour;
+        public readonly TaikoDifficultyHitObjectColour Colour;
 
         /// <summary>
         /// Creates a new difficulty hit object.
@@ -59,7 +58,7 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing
         /// <param name="objects">The list of all <see cref="DifficultyHitObject"/>s in the current beatmap.</param>
         /// <param name="centreHitObjects">The list of centre (don) <see cref="DifficultyHitObject"/>s in the current beatmap.</param>
         /// <param name="rimHitObjects">The list of rim (kat) <see cref="DifficultyHitObject"/>s in the current beatmap.</param>
-        /// <param name="noteObjects">The list of <see cref="DifficultyHitObject"/>s that is a hit (i.e. not a slider or spinner) in the current beatmap.</param>
+        /// <param name="noteObjects">The list of <see cref="DifficultyHitObject"/>s that is a hit (i.e. not a drumroll or swell) in the current beatmap.</param>
         /// <param name="index">The position of this <see cref="DifficultyHitObject"/> in the <paramref name="objects"/> list.</param>
         public TaikoDifficultyHitObject(HitObject hitObject, HitObject lastObject, HitObject lastLastObject, double clockRate,
                                         List<DifficultyHitObject> objects,
@@ -68,33 +67,31 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing
                                         List<TaikoDifficultyHitObject> noteObjects, int index)
             : base(hitObject, lastObject, clockRate, objects, index)
         {
-            // Create the Colour object, its properties should be filled in by TaikoDifficultyPreprocessor
-            Colour = new TaikoDifficultyHitObjectColour();
-
-            var currentHit = hitObject as Hit;
             noteDifficultyHitObjects = noteObjects;
 
+            // Create the Colour object, its properties should be filled in by TaikoDifficultyPreprocessor
+            Colour = new TaikoDifficultyHitObjectColour();
             Rhythm = getClosestRhythm(lastObject, lastLastObject, clockRate);
-            HitType? hitType = currentHit?.Type;
 
-            if (hitType == HitType.Centre)
+            switch ((hitObject as Hit)?.Type)
             {
-                MonoIndex = centreHitObjects.Count;
-                centreHitObjects.Add(this);
-                monoDifficultyHitObjects = centreHitObjects;
-            }
-            else if (hitType == HitType.Rim)
-            {
-                MonoIndex = rimHitObjects.Count;
-                rimHitObjects.Add(this);
-                monoDifficultyHitObjects = rimHitObjects;
-            }
+                case HitType.Centre:
+                    MonoIndex = centreHitObjects.Count;
+                    centreHitObjects.Add(this);
+                    monoDifficultyHitObjects = centreHitObjects;
+                    break;
 
-            // Need to be done after HitType is set.
-            if (hitType == null) return;
+                case HitType.Rim:
+                    MonoIndex = rimHitObjects.Count;
+                    rimHitObjects.Add(this);
+                    monoDifficultyHitObjects = rimHitObjects;
+                    break;
 
-            NoteIndex = noteObjects.Count;
-            noteObjects.Add(this);
+                default:
+                    NoteIndex = noteObjects.Count;
+                    noteObjects.Add(this);
+                    break;
+            }
         }
 
         /// <summary>
diff --git a/osu.Game.Rulesets.Taiko/Difficulty/Skills/Colour.cs b/osu.Game.Rulesets.Taiko/Difficulty/Skills/Colour.cs
index 386135ea4d..dac0beadda 100644
--- a/osu.Game.Rulesets.Taiko/Difficulty/Skills/Colour.cs
+++ b/osu.Game.Rulesets.Taiko/Difficulty/Skills/Colour.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Difficulty.Skills;
 using osu.Game.Rulesets.Mods;
diff --git a/osu.Game.Rulesets.Taiko/Difficulty/Skills/Peaks.cs b/osu.Game.Rulesets.Taiko/Difficulty/Skills/Peaks.cs
index 3e3bc543e1..ec8e754c5c 100644
--- a/osu.Game.Rulesets.Taiko/Difficulty/Skills/Peaks.cs
+++ b/osu.Game.Rulesets.Taiko/Difficulty/Skills/Peaks.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.Linq;