diff --git a/src/BizHawk.Client.Common/BitmapBufferVideoProvider.cs b/src/BizHawk.Client.Common/BitmapBufferVideoProvider.cs
index 2fa5282eb2..260cbb4db8 100644
--- a/src/BizHawk.Client.Common/BitmapBufferVideoProvider.cs
+++ b/src/BizHawk.Client.Common/BitmapBufferVideoProvider.cs
@@ -20,7 +20,7 @@ namespace BizHawk.Client.Common
 			_bb = null;
 		}
 
-		public int[] GetVideoBuffer() => _bb.Pixels;
+		public int[] GetVideoBuffer() => _bb.Pixels!;
 
 		public int VirtualWidth => _bb.Width;
 
diff --git a/src/BizHawk.Client.EmuHawk/QuickBmpFile.cs b/src/BizHawk.Client.EmuHawk/QuickBmpFile.cs
index 985e9006b9..afa513f280 100644
--- a/src/BizHawk.Client.EmuHawk/QuickBmpFile.cs
+++ b/src/BizHawk.Client.EmuHawk/QuickBmpFile.cs
@@ -218,10 +218,7 @@ namespace BizHawk.Client.EmuHawk
 		{
 			public int[] VideoBuffer { get; set; }
 
-			public int[] GetVideoBuffer()
-			{
-				return VideoBuffer;
-			}
+			public int[] GetVideoBuffer() => VideoBuffer!;
 
 			public int VirtualWidth => BufferWidth;
 
diff --git a/src/BizHawk.Emulation.Common/Interfaces/IEmulatorService.cs b/src/BizHawk.Emulation.Common/Interfaces/IEmulatorService.cs
index 9de958f107..cd2b2e2394 100644
--- a/src/BizHawk.Emulation.Common/Interfaces/IEmulatorService.cs
+++ b/src/BizHawk.Emulation.Common/Interfaces/IEmulatorService.cs
@@ -1,6 +1,4 @@
-#nullable disable
-
-namespace BizHawk.Emulation.Common
+namespace BizHawk.Emulation.Common
 {
 	/// <summary>
 	/// This interface specifies that an interface or implementation is a emulator core service, such as <seealso cref="IDebuggable"/>,
diff --git a/src/BizHawk.Emulation.Common/Interfaces/Services/IBoardInfo.cs b/src/BizHawk.Emulation.Common/Interfaces/Services/IBoardInfo.cs
index 3daba5307f..9e58fd1f11 100644
--- a/src/BizHawk.Emulation.Common/Interfaces/Services/IBoardInfo.cs
+++ b/src/BizHawk.Emulation.Common/Interfaces/Services/IBoardInfo.cs
@@ -1,6 +1,4 @@
-#nullable disable
-
-namespace BizHawk.Emulation.Common
+namespace BizHawk.Emulation.Common
 {
 	/// <summary>
 	/// An <seealso cref="IEmulatorService"/> that returns cart/mapper/board information about the Game hardware itself, if available
diff --git a/src/BizHawk.Emulation.Common/Interfaces/Services/ICreateGameDBEntries.cs b/src/BizHawk.Emulation.Common/Interfaces/Services/ICreateGameDBEntries.cs
index 437efc2080..bb14b5a328 100644
--- a/src/BizHawk.Emulation.Common/Interfaces/Services/ICreateGameDBEntries.cs
+++ b/src/BizHawk.Emulation.Common/Interfaces/Services/ICreateGameDBEntries.cs
@@ -1,6 +1,4 @@
-#nullable disable
-
-namespace BizHawk.Emulation.Common
+namespace BizHawk.Emulation.Common
 {
 	/// <summary>
 	/// This service provides a means for the current core to generate a
diff --git a/src/BizHawk.Emulation.Common/Interfaces/Services/ICycleTiming.cs b/src/BizHawk.Emulation.Common/Interfaces/Services/ICycleTiming.cs
index 61c92f2cad..9982216981 100644
--- a/src/BizHawk.Emulation.Common/Interfaces/Services/ICycleTiming.cs
+++ b/src/BizHawk.Emulation.Common/Interfaces/Services/ICycleTiming.cs
@@ -1,6 +1,4 @@
-#nullable disable
-
-namespace BizHawk.Emulation.Common
+namespace BizHawk.Emulation.Common
 {
 	public interface ICycleTiming
 	{
diff --git a/src/BizHawk.Emulation.Common/Interfaces/Services/IDriveLight.cs b/src/BizHawk.Emulation.Common/Interfaces/Services/IDriveLight.cs
index 64d976c9c3..122e414589 100644
--- a/src/BizHawk.Emulation.Common/Interfaces/Services/IDriveLight.cs
+++ b/src/BizHawk.Emulation.Common/Interfaces/Services/IDriveLight.cs
@@ -1,6 +1,4 @@
-#nullable disable
-
-namespace BizHawk.Emulation.Common
+namespace BizHawk.Emulation.Common
 {
 	/// <summary>
 	/// Specifies an interface for returning the state of a LED drive light such as on Disk and CD Drives,
diff --git a/src/BizHawk.Emulation.Common/Interfaces/Services/IInputPollable.cs b/src/BizHawk.Emulation.Common/Interfaces/Services/IInputPollable.cs
index 66a72905f7..468bf81fb6 100644
--- a/src/BizHawk.Emulation.Common/Interfaces/Services/IInputPollable.cs
+++ b/src/BizHawk.Emulation.Common/Interfaces/Services/IInputPollable.cs
@@ -1,6 +1,4 @@
-#nullable disable
-
-namespace BizHawk.Emulation.Common
+namespace BizHawk.Emulation.Common
 {
 	/// <summary>
 	/// This service specifies the interaction of the client and the core in terms of the state of input polling
diff --git a/src/BizHawk.Emulation.Common/Interfaces/Services/ILinkable.cs b/src/BizHawk.Emulation.Common/Interfaces/Services/ILinkable.cs
index 72f4ac5ecb..c406b57200 100644
--- a/src/BizHawk.Emulation.Common/Interfaces/Services/ILinkable.cs
+++ b/src/BizHawk.Emulation.Common/Interfaces/Services/ILinkable.cs
@@ -1,6 +1,4 @@
-#nullable disable
-
-namespace BizHawk.Emulation.Common
+namespace BizHawk.Emulation.Common
 {
 	/// <summary>
 	/// This service is use by link cable capable cores to manage the status of the link cable
diff --git a/src/BizHawk.Emulation.Common/Interfaces/Services/IRegionable.cs b/src/BizHawk.Emulation.Common/Interfaces/Services/IRegionable.cs
index 6a2ea5b693..26178d3da6 100644
--- a/src/BizHawk.Emulation.Common/Interfaces/Services/IRegionable.cs
+++ b/src/BizHawk.Emulation.Common/Interfaces/Services/IRegionable.cs
@@ -1,6 +1,4 @@
-#nullable disable
-
-namespace BizHawk.Emulation.Common
+namespace BizHawk.Emulation.Common
 {
 	/// <summary>
 	/// This service provides the means for a core to specify region information to the client, such NTSC versus PAL
diff --git a/src/BizHawk.Emulation.Common/Interfaces/Services/IRomInfo.cs b/src/BizHawk.Emulation.Common/Interfaces/Services/IRomInfo.cs
index df7573a225..d1c0a25302 100644
--- a/src/BizHawk.Emulation.Common/Interfaces/Services/IRomInfo.cs
+++ b/src/BizHawk.Emulation.Common/Interfaces/Services/IRomInfo.cs
@@ -1,6 +1,4 @@
-#nullable disable
-
-namespace BizHawk.Emulation.Common
+namespace BizHawk.Emulation.Common
 {
 	/// <summary>
 	/// Provides detailed information about the Rom such as hashes,
@@ -12,6 +10,6 @@ namespace BizHawk.Emulation.Common
 		/// All necessary information about the Rom.
 		/// Expected to be formatted for user consumption
 		/// </summary>
-		string RomDetails { get; }
+		string? RomDetails { get; }
 	}
 }
diff --git a/src/BizHawk.Emulation.Common/Interfaces/Services/IVideoOffset.cs b/src/BizHawk.Emulation.Common/Interfaces/Services/IVideoOffset.cs
index 3b04492e16..2515a9d7a3 100644
--- a/src/BizHawk.Emulation.Common/Interfaces/Services/IVideoOffset.cs
+++ b/src/BizHawk.Emulation.Common/Interfaces/Services/IVideoOffset.cs
@@ -1,6 +1,4 @@
-#nullable disable
-
-namespace BizHawk.Emulation.Common
+namespace BizHawk.Emulation.Common
 {
 	/// <summary>
 	/// Provides an interface to convey the effective X, Y coordinates that represent
diff --git a/src/BizHawk.Emulation.Common/Interfaces/Services/IVideoProvider.cs b/src/BizHawk.Emulation.Common/Interfaces/Services/IVideoProvider.cs
index 54dda91e4e..d6ecba85e6 100644
--- a/src/BizHawk.Emulation.Common/Interfaces/Services/IVideoProvider.cs
+++ b/src/BizHawk.Emulation.Common/Interfaces/Services/IVideoProvider.cs
@@ -1,6 +1,4 @@
-#nullable disable
-
-using System;
+using System;
 
 namespace BizHawk.Emulation.Common
 {
diff --git a/src/BizHawk.Emulation.Cores/Computers/AmstradCPC/Hardware/Display/CRTDevice.cs b/src/BizHawk.Emulation.Cores/Computers/AmstradCPC/Hardware/Display/CRTDevice.cs
index 6399bad049..06461dadcb 100644
--- a/src/BizHawk.Emulation.Cores/Computers/AmstradCPC/Hardware/Display/CRTDevice.cs
+++ b/src/BizHawk.Emulation.Cores/Computers/AmstradCPC/Hardware/Display/CRTDevice.cs
@@ -200,7 +200,7 @@ namespace BizHawk.Emulation.Cores.Computers.AmstradCPC
 
 		public int VsyncDenominator => GateArray.Z80ClockSpeed;
 
-		public int[] GetVideoBuffer() => ProcessVideoBuffer();
+		public int[] GetVideoBuffer() => ProcessVideoBuffer()!;
 
 		public void SetupScreenSize()
 		{