diff --git a/osu.Desktop.VisualTests/Tests/TestCaseManiaHitObjects.cs b/osu.Desktop.VisualTests/Tests/TestCaseManiaHitObjects.cs
index 97c65b799b..4368e8488c 100644
--- a/osu.Desktop.VisualTests/Tests/TestCaseManiaHitObjects.cs
+++ b/osu.Desktop.VisualTests/Tests/TestCaseManiaHitObjects.cs
@@ -6,11 +6,6 @@ using osu.Framework.Graphics.Containers;
 using osu.Framework.Testing;
 using osu.Game.Rulesets.Mania.Objects;
 using osu.Game.Rulesets.Mania.Objects.Drawables;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 using OpenTK.Graphics;
 using OpenTK;
 
diff --git a/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs b/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs
index 8e4fd83956..08ee8c0bf8 100644
--- a/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs
+++ b/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs
@@ -8,7 +8,6 @@ using System;
 using osu.Game.Rulesets.Objects.Types;
 using osu.Game.Rulesets.Beatmaps;
 using osu.Game.Rulesets.Objects;
-using osu.Game.Rulesets.Mania.Objects.Drawables;
 
 namespace osu.Game.Rulesets.Mania.Beatmaps
 {
diff --git a/osu.Game.Rulesets.Mania/Objects/Drawables/DrawableHoldNote.cs b/osu.Game.Rulesets.Mania/Objects/Drawables/DrawableHoldNote.cs
index b6943a95ce..61dc2638a6 100644
--- a/osu.Game.Rulesets.Mania/Objects/Drawables/DrawableHoldNote.cs
+++ b/osu.Game.Rulesets.Mania/Objects/Drawables/DrawableHoldNote.cs
@@ -1,21 +1,18 @@
 // Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
-using System;
 using osu.Game.Rulesets.Objects.Drawables;
 using osu.Framework.Graphics;
-using osu.Framework.Allocation;
 using osu.Game.Rulesets.Mania.Objects.Drawables.Pieces;
 using OpenTK.Graphics;
-using osu.Framework.Graphics.Containers;
 
 namespace osu.Game.Rulesets.Mania.Objects.Drawables
 {
     public class DrawableHoldNote : DrawableManiaHitObject<HoldNote>
     {
-        private NotePiece headPiece;
-        private BodyPiece bodyPiece;
-        private NotePiece tailPiece;
+        private readonly NotePiece headPiece;
+        private readonly BodyPiece bodyPiece;
+        private readonly NotePiece tailPiece;
 
         public DrawableHoldNote(HoldNote hitObject)
             : base(hitObject)
@@ -52,7 +49,7 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
 
         public override Color4 AccentColour
         {
-            get { return AccentColour; }
+            get { return base.AccentColour; }
             set
             {
                 if (base.AccentColour == value)
diff --git a/osu.Game.Rulesets.Mania/Objects/Drawables/DrawableManiaHitObject.cs b/osu.Game.Rulesets.Mania/Objects/Drawables/DrawableManiaHitObject.cs
index 14d930893f..e3b28c8aca 100644
--- a/osu.Game.Rulesets.Mania/Objects/Drawables/DrawableManiaHitObject.cs
+++ b/osu.Game.Rulesets.Mania/Objects/Drawables/DrawableManiaHitObject.cs
@@ -2,7 +2,6 @@
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using OpenTK.Graphics;
-using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Sprites;
@@ -18,7 +17,7 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
 
         private readonly Container glowContainer;
 
-        public DrawableManiaHitObject(TObject hitObject)
+        protected DrawableManiaHitObject(TObject hitObject)
             : base(hitObject)
         {
             HitObject = hitObject;
diff --git a/osu.Game.Rulesets.Mania/Objects/Drawables/DrawableNote.cs b/osu.Game.Rulesets.Mania/Objects/Drawables/DrawableNote.cs
index 393ddfb3e0..8832fc8d48 100644
--- a/osu.Game.Rulesets.Mania/Objects/Drawables/DrawableNote.cs
+++ b/osu.Game.Rulesets.Mania/Objects/Drawables/DrawableNote.cs
@@ -2,10 +2,7 @@
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using OpenTK.Graphics;
-using osu.Framework.Allocation;
 using osu.Framework.Graphics;
-using osu.Framework.Graphics.Containers;
-using osu.Framework.Graphics.Sprites;
 using osu.Game.Rulesets.Mania.Objects.Drawables.Pieces;
 using osu.Game.Rulesets.Objects.Drawables;
 
@@ -13,7 +10,7 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
 {
     public class DrawableNote : DrawableManiaHitObject<Note>
     {
-        private NotePiece headPiece;
+        private readonly NotePiece headPiece;
 
         public DrawableNote(Note hitObject)
             : base(hitObject)
@@ -30,7 +27,7 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
 
         public override Color4 AccentColour
         {
-            get { return AccentColour; }
+            get { return base.AccentColour; }
             set
             {
                 if (base.AccentColour == value)
diff --git a/osu.Game.Rulesets.Mania/Objects/Drawables/Pieces/BodyPiece.cs b/osu.Game.Rulesets.Mania/Objects/Drawables/Pieces/BodyPiece.cs
index ac2b7df06f..ce61a7a86f 100644
--- a/osu.Game.Rulesets.Mania/Objects/Drawables/Pieces/BodyPiece.cs
+++ b/osu.Game.Rulesets.Mania/Objects/Drawables/Pieces/BodyPiece.cs
@@ -1,7 +1,6 @@
 // Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
-using System;
 using OpenTK.Graphics;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -15,7 +14,7 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables.Pieces
     /// </summary>
     internal class BodyPiece : Container, IHasAccentColour
     {
-        private Box box;
+        private readonly Box box;
 
         public BodyPiece()
         {
diff --git a/osu.Game.Rulesets.Mania/Objects/Drawables/Pieces/NotePiece.cs b/osu.Game.Rulesets.Mania/Objects/Drawables/Pieces/NotePiece.cs
index 2584682833..e01199e929 100644
--- a/osu.Game.Rulesets.Mania/Objects/Drawables/Pieces/NotePiece.cs
+++ b/osu.Game.Rulesets.Mania/Objects/Drawables/Pieces/NotePiece.cs
@@ -18,7 +18,7 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables.Pieces
         private const float head_height = 10;
         private const float head_colour_height = 6;
 
-        private Box colouredBox;
+        private readonly Box colouredBox;
 
         public NotePiece()
         {
diff --git a/osu.Game.Rulesets.Mania/Timing/DrawableTimingSection.cs b/osu.Game.Rulesets.Mania/Timing/DrawableTimingSection.cs
index b5943c272a..2225a63cdf 100644
--- a/osu.Game.Rulesets.Mania/Timing/DrawableTimingSection.cs
+++ b/osu.Game.Rulesets.Mania/Timing/DrawableTimingSection.cs
@@ -1,12 +1,10 @@
 // Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
-using System;
 using OpenTK;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 
-
 namespace osu.Game.Rulesets.Mania.Timing
 {
     /// <summary>
diff --git a/osu.Game.Rulesets.Mania/UI/Column.cs b/osu.Game.Rulesets.Mania/UI/Column.cs
index a140fa1984..abfa3c921b 100644
--- a/osu.Game.Rulesets.Mania/UI/Column.cs
+++ b/osu.Game.Rulesets.Mania/UI/Column.cs
@@ -14,8 +14,6 @@ using osu.Framework.Input;
 using osu.Game.Graphics;
 using osu.Game.Rulesets.Mania.Timing;
 using System.Collections.Generic;
-using osu.Framework.Extensions.IEnumerableExtensions;
-using osu.Framework.Graphics.Primitives;
 using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Rulesets.Mania.Objects;
 using osu.Game.Rulesets.Mania.Judgements;
diff --git a/osu.Game.Rulesets.Mania/UI/ManiaHitRenderer.cs b/osu.Game.Rulesets.Mania/UI/ManiaHitRenderer.cs
index 20a7d9983e..b6dae3dfe9 100644
--- a/osu.Game.Rulesets.Mania/UI/ManiaHitRenderer.cs
+++ b/osu.Game.Rulesets.Mania/UI/ManiaHitRenderer.cs
@@ -4,8 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using osu.Framework.Allocation;
-using osu.Framework.Extensions.IEnumerableExtensions;
 using osu.Game.Beatmaps;
 using osu.Game.Beatmaps.Timing;
 using osu.Game.Rulesets.Beatmaps;
diff --git a/osu.Game.Rulesets.Mania/UI/ManiaPlayfield.cs b/osu.Game.Rulesets.Mania/UI/ManiaPlayfield.cs
index 4572239b55..8cf792dbb0 100644
--- a/osu.Game.Rulesets.Mania/UI/ManiaPlayfield.cs
+++ b/osu.Game.Rulesets.Mania/UI/ManiaPlayfield.cs
@@ -18,7 +18,6 @@ using System.Linq;
 using System.Collections.Generic;
 using osu.Framework.Extensions.IEnumerableExtensions;
 using osu.Game.Rulesets.Objects.Drawables;
-using osu.Game.Rulesets.Mania.Objects.Drawables;
 using osu.Game.Rulesets.Mania.Timing;
 using osu.Framework.Input;
 
diff --git a/osu.Game.Rulesets.Mania/UI/TimingSectionContainer.cs b/osu.Game.Rulesets.Mania/UI/TimingSectionContainer.cs
index a43d107341..9a63c17c59 100644
--- a/osu.Game.Rulesets.Mania/UI/TimingSectionContainer.cs
+++ b/osu.Game.Rulesets.Mania/UI/TimingSectionContainer.cs
@@ -6,10 +6,7 @@ using System.Linq;
 using OpenTK;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
-using osu.Game.Rulesets.Mania.Judgements;
-using osu.Game.Rulesets.Mania.Objects;
 using osu.Game.Rulesets.Mania.Timing;
-using osu.Game.Rulesets.Objects.Drawables;
 
 namespace osu.Game.Rulesets.Mania.UI
 {
@@ -32,7 +29,7 @@ namespace osu.Game.Rulesets.Mania.UI
         public void Add(Drawable drawable)
         {
             var section = Children.LastOrDefault(t => t.Y >= drawable.Y) ?? Children.First();
-            drawable.Y -= (float)section.Y;
+            drawable.Y -= section.Y;
             section.Add(drawable);
         }
     }
diff --git a/osu.Game/Rulesets/Objects/Drawables/DrawableHitObject.cs b/osu.Game/Rulesets/Objects/Drawables/DrawableHitObject.cs
index f443b5e279..8e153415c7 100644
--- a/osu.Game/Rulesets/Objects/Drawables/DrawableHitObject.cs
+++ b/osu.Game/Rulesets/Objects/Drawables/DrawableHitObject.cs
@@ -183,7 +183,7 @@ namespace osu.Game.Rulesets.Objects.Drawables
             }
         }
 
-        private List<DrawableHitObject<TObject, TJudgement>> nestedHitObjects = new List<DrawableHitObject<TObject, TJudgement>>();
+        private readonly List<DrawableHitObject<TObject, TJudgement>> nestedHitObjects = new List<DrawableHitObject<TObject, TJudgement>>();
         protected IEnumerable<DrawableHitObject<TObject, TJudgement>> NestedHitObjects => nestedHitObjects;
 
         protected void AddNested(DrawableHitObject<TObject, TJudgement> h)
diff --git a/osu.Game/Rulesets/UI/HitRenderer.cs b/osu.Game/Rulesets/UI/HitRenderer.cs
index cbca4fbfa2..52b7a2766a 100644
--- a/osu.Game/Rulesets/UI/HitRenderer.cs
+++ b/osu.Game/Rulesets/UI/HitRenderer.cs
@@ -199,7 +199,7 @@ namespace osu.Game.Rulesets.UI
         protected override Container<Drawable> Content => content;
         private readonly Container content;
 
-        private List<DrawableHitObject<TObject, TJudgement>> drawableObjects = new List<DrawableHitObject<TObject, TJudgement>>();
+        private readonly List<DrawableHitObject<TObject, TJudgement>> drawableObjects = new List<DrawableHitObject<TObject, TJudgement>>();
 
         protected HitRenderer(WorkingBeatmap beatmap)
             : base(beatmap)