diff --git a/BizHawk.Client.Common/rewind/Rewinder.cs b/BizHawk.Client.Common/rewind/Rewinder.cs
index 46cbd58c92..d65582965e 100644
--- a/BizHawk.Client.Common/rewind/Rewinder.cs
+++ b/BizHawk.Client.Common/rewind/Rewinder.cs
@@ -31,17 +31,17 @@ namespace BizHawk.Client.Common
 
 		public float FullnessRatio
 		{
-			get { return _rewindBuffer != null ? _rewindBuffer.FullnessRatio : 0; }
+			get { return _rewindBuffer?.FullnessRatio ?? 0; }
 		}
 
 		public int Count
 		{
-			get { return _rewindBuffer != null ? _rewindBuffer.Count : 0; }
+			get { return _rewindBuffer?.Count ?? 0; }
 		}
 
 		public long Size
 		{
-			get { return _rewindBuffer != null ? _rewindBuffer.Size : 0; }
+			get { return _rewindBuffer?.Size ?? 0; }
 		}
 
 		public bool HasBuffer
@@ -116,10 +116,7 @@ namespace BizHawk.Client.Common
 
 		private void DoMessage(string message)
 		{
-			if (MessageCallback != null)
-			{
-				MessageCallback(message);
-			}
+			MessageCallback?.Invoke(message);
 		}
 
 		private void SetRewindParams(bool enabled, int frequency)
diff --git a/BizHawk.Client.EmuHawk/Sound/Output/DirectSoundSoundOutput.cs b/BizHawk.Client.EmuHawk/Sound/Output/DirectSoundSoundOutput.cs
index ec1a19b549..42af277c0e 100644
--- a/BizHawk.Client.EmuHawk/Sound/Output/DirectSoundSoundOutput.cs
+++ b/BizHawk.Client.EmuHawk/Sound/Output/DirectSoundSoundOutput.cs
@@ -103,7 +103,7 @@ namespace BizHawk.Client.EmuHawk
 			_lastWriteTime = 0;
 			_lastWriteCursor = 0;
 
-			_deviceBuffer.Play(0, SlimDX.DirectSound.PlayFlags.Looping);
+			_deviceBuffer.Play(0, PlayFlags.Looping);
 		}
 
 		public void StopSound()
diff --git a/BizHawk.Client.EmuHawk/Sound/Output/OpenALSoundOutput.cs b/BizHawk.Client.EmuHawk/Sound/Output/OpenALSoundOutput.cs
index 4a24bb4d82..263a18c5be 100644
--- a/BizHawk.Client.EmuHawk/Sound/Output/OpenALSoundOutput.cs
+++ b/BizHawk.Client.EmuHawk/Sound/Output/OpenALSoundOutput.cs
@@ -86,7 +86,7 @@ namespace BizHawk.Client.EmuHawk
 				currentSamplesPlayed = 0;
 			}
 			int samplesAwaitingPlayback = _currentSamplesQueued - currentSamplesPlayed;
-			int samplesNeeded = (int)Math.Max(BufferSizeSamples - samplesAwaitingPlayback, 0);
+			int samplesNeeded = Math.Max(BufferSizeSamples - samplesAwaitingPlayback, 0);
 			if (isInitializing || detectedUnderrun)
 			{
 				_sound.HandleInitializationOrUnderrun(detectedUnderrun, ref samplesNeeded);
diff --git a/BizHawk.Client.EmuHawk/UpdateChecker.cs b/BizHawk.Client.EmuHawk/UpdateChecker.cs
index 5c7ba68c14..6b61290213 100644
--- a/BizHawk.Client.EmuHawk/UpdateChecker.cs
+++ b/BizHawk.Client.EmuHawk/UpdateChecker.cs
@@ -134,9 +134,9 @@ namespace BizHawk.Client.EmuHawk
 
 		private static void OnCheckComplete()
 		{
-			CheckComplete(null, EventArgs.Empty);
+			CheckComplete?.Invoke(null, EventArgs.Empty);
 		}
 
-		public static event EventHandler CheckComplete = delegate { };
+		public static event EventHandler CheckComplete;
 	}
 }