diff --git a/resourcefile.h b/resourcefile.h
index d94c401..73a168f 100644
--- a/resourcefile.h
+++ b/resourcefile.h
@@ -28,8 +28,7 @@ class CWADFile
 	uint64_t m_LumpStart;
 	
 public:
-	CWADFile(const char * filename);
-	CWADFile(const char * name, const char * memory);
+	CWADFile(const char * filename, FILE* f);
 	~CWADFile(void);
 
 	const char * GetName() const
diff --git a/wadext.cpp b/wadext.cpp
index 16511d1..d9b9dbe 100644
--- a/wadext.cpp
+++ b/wadext.cpp
@@ -670,3 +670,64 @@ void ConvertTextureX()
 	if (ft2) GenerateTextureFile("textures.txt2", bt2, bpn, 0, false);
 }
 
+//==========================================================================
+//
+//
+//
+//==========================================================================
+
+struct GrpInfo
+{
+	uint32_t		Magic[3];
+	uint32_t		NumLumps;
+};
+
+struct GrpLump
+{
+	union
+	{
+		struct
+		{
+			char		Name[12];
+			uint32_t		Size;
+		};
+		char NameWithZero[13];
+	};
+};
+
+
+void GrpExtract(const char* filename, FILE* f)
+{
+	TArray<GrpLump> fileinfo;
+
+	GrpInfo header;
+
+	if (1 != fread(&header, sizeof(header), 1, f)) return;
+
+	fileinfo.Resize(header.NumLumps);
+	if (header.NumLumps != fread(&fileinfo[0], sizeof(GrpLump), header.NumLumps, f)) return;
+	if (memcmp(header.Magic, "KenSilverman", 12))
+	{
+		return;
+	}
+
+	auto name = ExtractFileBase(filename, false);
+	mkdir(name.c_str());
+	chdir(name.c_str());
+
+	TArray<char> buffer;
+	for (uint32_t i = 0; i < header.NumLumps; i++)
+	{
+		buffer.Resize(fileinfo[i].Size);
+		fileinfo[i].NameWithZero[12] = '\0';	// Be sure filename is null-terminated
+		if (fileinfo[i].Size != fread(&buffer[0], 1, fileinfo[i].Size, f)) return;
+		FILE* fout = fopen(fileinfo[i].NameWithZero, "wb");
+		if (fout)
+		{
+			fwrite(&buffer[0], 1, fileinfo[i].Size, fout);
+			fclose(fout);
+		}
+	}
+	exit(1);
+}
+
diff --git a/wadfile.cpp b/wadfile.cpp
index c02463a..0ebfa3d 100644
--- a/wadfile.cpp
+++ b/wadfile.cpp
@@ -30,7 +30,7 @@
 //
 //==========================================================================
 
-CWADFile::CWADFile(const char * filename)
+CWADFile::CWADFile(const char * filename, FILE* f)
 {
 	char type[4];
 	int diroffset;
@@ -40,20 +40,6 @@ CWADFile::CWADFile(const char * filename)
 	m_LumpStart=0;
 	
 	m_Filename = strdup(filename);
-	m_File=NULL;
-
-	if (filename == NULL)
-	{
-		printf("No file name specified\n");
-		return;
-	}
-
-	FILE *f = fopen(filename, "rb");
-	if (!f)
-	{
-		printf("%s: unable to open\n", filename);
-		return;
-	}
 
 	m_File = f;
 	fread(&type, 1, 4, f);
@@ -172,6 +158,14 @@ const char * CWADFile::GetLumpName(int lump)
 	}
 }
 
+//==========================================================================
+//
+//
+//
+//==========================================================================
+
+void GrpExtract(const char* filename, FILE* f);
+
 //==========================================================================
 //
 //
@@ -181,9 +175,38 @@ CWADFile *mainwad;
 
 void OpenMainWad(char *filename)
 {
-	mainwad = new CWADFile(filename);
-	if (mainwad->NumLumps() == 0)
+	if (filename == NULL)
 	{
+		printf("No file name specified\n");
 		exit(1);
 	}
+
+	FILE *f = fopen(filename, "rb");
+	if (!f)
+	{
+		printf("%s: unable to open\n", filename);
+		exit(1);
+	}
+
+
+	char type[4];
+	fread(&type, 1, 4, f);
+	fseek(f, 0, SEEK_SET);
+
+	if (memcmp(type, "IWAD", 4) == 0 || memcmp(type, "PWAD", 4) == 0)
+	{
+		mainwad = new CWADFile(filename, f);
+		if (mainwad->NumLumps() == 0)
+		{
+			exit(1);
+		}
+	}
+	else if (memcmp(type, "KenS", 4) == 0)
+	{
+		GrpExtract(filename, f);
+		exit(1);
+	}
+	printf("%s: not a WAD file\n", filename);
+	exit(1);
 }
+