diff --git a/src/d_main.c b/src/d_main.c
index 811fb2c0..88425f3a 100644
--- a/src/d_main.c
+++ b/src/d_main.c
@@ -608,7 +608,7 @@ static boolean D_AddZipFile(const char *file)
   char *str, *tempdir, counter[8];
   static int idx = 0;
 
-  if (!M_StringCaseEndsWith(file, ".zip") && !M_StringEndsWith(file, ".pk3"))
+  if (!M_StringCaseEndsWith(file, ".zip") && !M_StringCaseEndsWith(file, ".pk3"))
   {
     return false;
   }
@@ -617,7 +617,6 @@ static boolean D_AddZipFile(const char *file)
   if (!mz_zip_reader_init_file(&zip_archive, file, MZ_ZIP_FLAG_DO_NOT_SORT_CENTRAL_DIRECTORY))
   {
     I_Error("D_AddZipFile: Failed to open %s", file);
-    return false;
   }
 
   M_snprintf(counter, sizeof(counter), "%04d", idx);
@@ -864,7 +863,6 @@ static void CheckIWAD(const char *iwadname)
     {
         fclose(file);
         I_Error("CheckIWAD: failed to read header %s", iwadname);
-        return;
     }
 
     if (strncmp(header.identification, "IWAD", 4) &&
@@ -872,7 +870,6 @@ static void CheckIWAD(const char *iwadname)
     {
         fclose(file);
         I_Error("Wad file %s doesn't have IWAD or PWAD id\n", iwadname);
-        return;
     }
 
     // read IWAD directory
@@ -886,7 +883,6 @@ static void CheckIWAD(const char *iwadname)
         free(fileinfo);
         fclose(file);
         I_Error("CheckIWAD: failed to read directory %s", iwadname);
-        return;
     }
 
     for (i = 0; i < header.numlumps; ++i)
diff --git a/src/doomtype.h b/src/doomtype.h
index 4d356c61..5f4899ca 100644
--- a/src/doomtype.h
+++ b/src/doomtype.h
@@ -83,10 +83,16 @@ typedef uint8_t pixel_t;
 #if defined(__GNUC__) || defined(__clang__)
  #define PRINTF_ATTR(fmt, first) __attribute__((format(printf, fmt, first)))
  #define PRINTF_ARG_ATTR(x) __attribute__((format_arg(x)))
- #define NORETURN __attribute__((noreturn))
 #else
  #define PRINTF_ATTR(fmt, first)
  #define PRINTF_ARG_ATTR(x)
+#endif
+
+#if defined(__GNUC__) || defined(__clang__)
+ #define NORETURN __attribute__((noreturn))
+#elif defined (_MSC_VER)
+ #define NORETURN __declspec(noreturn)
+#else
  #define NORETURN
 #endif
 
diff --git a/src/i_system.h b/src/i_system.h
index 2e95dd97..23741c15 100644
--- a/src/i_system.h
+++ b/src/i_system.h
@@ -60,7 +60,7 @@ ticcmd_t* I_BaseTiccmd (void);
 
 // killough 3/20/98: add const
 // killough 4/25/98: add gcc attributes
-void I_ErrorOrSuccess(int err_code, const char *error, ...) NORETURN PRINTF_ATTR(2, 3);
+NORETURN void I_ErrorOrSuccess(int err_code, const char *error, ...) PRINTF_ATTR(2, 3);
 #define I_Error(...) I_ErrorOrSuccess(-1, __VA_ARGS__)
 #define I_Success(...) I_ErrorOrSuccess(0, __VA_ARGS__)
 
@@ -81,7 +81,7 @@ typedef void (*atexit_func_t)(void);
 void I_AtExitPrio(atexit_func_t func, boolean run_if_error,
                   const char* name, exit_priority_t priority);
 #define I_AtExit(a,b) I_AtExitPrio(a,b,#a,exit_priority_normal)
-void I_SafeExit(int rc) NORETURN;
+NORETURN void I_SafeExit(int rc);
 void I_ErrorMsg(void);
 
 void *I_Realloc(void *ptr, size_t size);