diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 4753869..cca36e6 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -29,7 +29,17 @@ if(WIN32)
     add_definitions(-DDISCORD_WINDOWS)
     set(BASE_RPC_SRC ${BASE_RPC_SRC} connection_win.cpp discord_register_win.cpp)
     add_library(discord-rpc ${RPC_LIBRARY_TYPE} ${BASE_RPC_SRC})
-    target_compile_options(discord-rpc PRIVATE /W4)
+    target_compile_options(discord-rpc PRIVATE /EHsc
+        /Wall
+        /wd4514 # unreferenced inline
+        /wd4625 # copy constructor deleted
+        /wd5026 # move constructor deleted
+        /wd4626 # move assignment operator deleted
+        /wd4710 # function not inlined
+        /wd4820 # structure padding
+        /wd4946 # reinterpret_cast used between related classes
+        /wd5027 # move assignment operator was implicitly defined as deleted
+    )
 endif(WIN32)
 
 if(UNIX)
@@ -88,4 +98,4 @@ install(
     FILES
         "../include/discord-rpc.h"
     DESTINATION "include"
-)
\ No newline at end of file
+)
diff --git a/src/backoff.h b/src/backoff.h
index e26f417..9d5011c 100644
--- a/src/backoff.h
+++ b/src/backoff.h
@@ -20,7 +20,7 @@ struct Backoff {
       , maxAmount(max)
       , current(min)
       , fails(0)
-      , randGenerator(time(0))
+      , randGenerator((uint64_t)time(0))
     {
     }
 
diff --git a/src/connection_win.cpp b/src/connection_win.cpp
index fa80570..9790e8f 100644
--- a/src/connection_win.cpp
+++ b/src/connection_win.cpp
@@ -9,7 +9,7 @@
 
 int GetProcessId()
 {
-    return ::GetCurrentProcessId();
+    return (int)::GetCurrentProcessId();
 }
 
 struct BaseConnectionWin : public BaseConnection {
@@ -125,4 +125,4 @@ bool BaseConnection::Read(void* data, size_t length)
         Close();
     }
     return false;
-}
\ No newline at end of file
+}
diff --git a/src/discord_register_win.cpp b/src/discord_register_win.cpp
index 8ac5b42..8eed2f0 100644
--- a/src/discord_register_win.cpp
+++ b/src/discord_register_win.cpp
@@ -17,9 +17,8 @@ void Discord_RegisterW(const wchar_t* applicationId, const wchar_t* command)
     // Update the HKEY_CURRENT_USER, because it doesn't seem to require special permissions.
 
     wchar_t exeFilePath[MAX_PATH];
-    int exeLen = GetModuleFileNameExW(GetCurrentProcess(), nullptr, exeFilePath, MAX_PATH);
+    DWORD exeLen = GetModuleFileNameExW(GetCurrentProcess(), nullptr, exeFilePath, MAX_PATH);
     wchar_t openCommand[1024];
-    const auto commandBufferLen = sizeof(openCommand) / sizeof(*openCommand);
 
     if (command && command[0]) {
         StringCbPrintfW(openCommand, sizeof(openCommand), L"%s", command);
@@ -46,14 +45,14 @@ void Discord_RegisterW(const wchar_t* applicationId, const wchar_t* command)
     }
     DWORD len;
     LSTATUS result;
-    len = lstrlenW(protocolDescription) + 1;
+    len = (DWORD)lstrlenW(protocolDescription) + 1;
     result =
       RegSetKeyValueW(key, nullptr, nullptr, REG_SZ, protocolDescription, len * sizeof(wchar_t));
     if (FAILED(result)) {
         fprintf(stderr, "Error writing description\n");
     }
 
-    len = lstrlenW(protocolDescription) + 1;
+    len = (DWORD)lstrlenW(protocolDescription) + 1;
     result = RegSetKeyValueW(key, nullptr, L"URL Protocol", REG_SZ, &urlProtocol, sizeof(wchar_t));
     if (FAILED(result)) {
         fprintf(stderr, "Error writing description\n");
@@ -65,7 +64,7 @@ void Discord_RegisterW(const wchar_t* applicationId, const wchar_t* command)
         fprintf(stderr, "Error writing icon\n");
     }
 
-    len = lstrlenW(openCommand) + 1;
+    len = (DWORD)lstrlenW(openCommand) + 1;
     result = RegSetKeyValueW(
       key, L"shell\\open\\command", nullptr, REG_SZ, openCommand, len * sizeof(wchar_t));
     if (FAILED(result)) {
diff --git a/src/rpc_connection.cpp b/src/rpc_connection.cpp
index e1e9328..b492de9 100644
--- a/src/rpc_connection.cpp
+++ b/src/rpc_connection.cpp
@@ -129,6 +129,7 @@ bool RpcConnection::Read(JsonDocument& message)
             break;
         case Opcode::Pong:
             break;
+        case Opcode::Handshake:
         default:
             // something bad happened
             lastErrorCode = (int)ErrorCode::ReadCorrupt;
diff --git a/src/serialization.h b/src/serialization.h
index 360bde9..8bc9fa7 100644
--- a/src/serialization.h
+++ b/src/serialization.h
@@ -2,10 +2,20 @@
 
 #include <stdint.h>
 
+#pragma warning(push)
+
+#pragma warning(disable : 4061) // enum is not explicitly handled by a case label
+#pragma warning(disable : 4365) // signed/unsigned mismatch
+#pragma warning(disable : 4464) // relative include path contains
+#pragma warning(disable : 4668) // is not defined as a preprocessor macro
+#pragma warning(disable : 6313) // Incorrect operator
+
 #include "rapidjson/document.h"
 #include "rapidjson/writer.h"
 #include "rapidjson/stringbuffer.h"
 
+#pragma warning(pop)
+
 // if only there was a standard library function for this
 template <size_t Len>
 inline size_t StringCopy(char (&dest)[Len], const char* src)
@@ -111,7 +121,7 @@ public:
         }
     }
     void Flush() {}
-    size_t GetSize() const { return current_ - buffer_; }
+    size_t GetSize() const { return (size_t)(current_ - buffer_); }
 };
 
 using MallocAllocator = rapidjson::CrtAllocator;