diff --git a/ArcFormats/ArcEGO.cs b/ArcFormats/ArcEGO.cs
new file mode 100644
index 00000000..74444ff3
--- /dev/null
+++ b/ArcFormats/ArcEGO.cs
@@ -0,0 +1,155 @@
+//! \file       ArcEGO.cs
+//! \date       Mon Mar 30 21:03:11 2015
+//! \brief      Studio e.go! engine resource archives.
+//
+// Copyright (C) 2015 by morkt
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.IO;
+using System.Text;
+using GameRes.Formats.Strings;
+using GameRes.Utility;
+
+namespace GameRes.Formats.Ego
+{
+    [Export(typeof(ArchiveFormat))]
+    public class DatOpener : ArchiveFormat
+    {
+        public override string         Tag { get { return "EGO"; } }
+        public override string Description { get { return "Studio e.go! engine resource archive"; } }
+        public override uint     Signature { get { return 0; } }
+        public override bool  IsHierarchic { get { return true; } }
+        public override bool     CanCreate { get { return true; } }
+
+        public DatOpener ()
+        {
+            Extensions = new string[] { "dat" };
+        }
+
+        public override ArcFile TryOpen (ArcView file)
+        {
+            uint data_offset = 4 + file.View.ReadUInt32 (0);
+            if (data_offset <= 0x14 || data_offset >= file.MaxOffset)
+                return null;
+            var dir = new List<Entry>();
+            long index_offset = 4;
+            while (index_offset < data_offset)
+            {
+                uint entry_len = file.View.ReadUInt32 (index_offset);
+                if (entry_len <= 0x10 || entry_len > 0x100 || index_offset + entry_len > data_offset)
+                    return null;
+                var name = file.View.ReadString (index_offset+0x10, entry_len-0x10);
+                var entry = FormatCatalog.Instance.CreateEntry (name);
+                entry.Offset = file.View.ReadUInt32 (index_offset+8);
+                entry.Size   = file.View.ReadUInt32 (index_offset+12);
+                if (entry.Offset < data_offset || !entry.CheckPlacement (file.MaxOffset))
+                    return null;
+                dir.Add (entry);
+                index_offset += entry_len;
+            }
+            return new ArcFile (file, this, dir);
+        }
+
+        public override void Create (Stream output, IEnumerable<Entry> list, ResourceOptions options,
+                                     EntryCallback callback)
+        {
+            using (var writer = new BinaryWriter (output, Encoding.ASCII, true))
+            {
+                var encoding = Encodings.cp932.WithFatalFallback();
+                int callback_count = 0;
+                if (null != callback)
+                    callback (callback_count++, null, arcStrings.MsgWritingIndex);
+
+                writer.Write (0);
+                byte[] name_buf = new byte[256];
+                uint index_size = 0;
+                var entry_sizes = new List<int>();
+
+                // first, write names only
+                foreach (var entry in list)
+                {
+                    try
+                    {
+                        int size = encoding.GetBytes (entry.Name, 0, entry.Name.Length, name_buf, 0);
+                        if (name_buf.Length == size)
+                            throw new InvalidFileName (entry.Name, arcStrings.MsgFileNameTooLong);
+                        name_buf[size] = 0;
+                        int entry_size = size+17;
+                        writer.Write (entry_size);
+                        writer.BaseStream.Seek (12, SeekOrigin.Current);
+                        writer.Write (name_buf, 0, size+1);
+                        entry_sizes.Add (entry_size);
+                        index_size += (uint)entry_size;
+                    }
+                    catch (EncoderFallbackException X)
+                    {
+                        throw new InvalidFileName (entry.Name, arcStrings.MsgIllegalCharacters, X);
+                    }
+                    catch (ArgumentException X)
+                    {
+                        throw new InvalidFileName (entry.Name, arcStrings.MsgFileNameTooLong, X);
+                    }
+                }
+
+                // now, write files and remember offset/sizes
+                long current_offset = writer.BaseStream.Position;
+                foreach (var entry in list)
+                {
+                    if (null != callback)
+                        callback (callback_count++, entry, arcStrings.MsgAddingFile);
+
+                    entry.Offset = current_offset;
+                    using (var input = File.OpenRead (entry.Name))
+                    {
+                        var file_size = input.Length;
+                        if (file_size > uint.MaxValue || current_offset + file_size > uint.MaxValue)
+                            throw new FileSizeException();
+                        current_offset += file_size;
+                        entry.Size = (uint)file_size;
+                        input.CopyTo (output);
+                    }
+                }
+
+                if (null != callback)
+                    callback (callback_count++, null, arcStrings.MsgUpdatingIndex);
+
+                // at last, go back to directory and write offset/sizes
+                writer.BaseStream.Position = 0;
+                writer.Write (index_size);
+                long index_offset = 4+8;
+                int i = 0;
+                foreach (var entry in list)
+                {
+                    writer.BaseStream.Position = index_offset;
+                    int entry_size = entry_sizes[i++];
+                    index_offset += entry_size;
+                    writer.Write ((uint)entry.Offset);
+                    writer.Write (entry.Size);
+                }
+            }
+        }
+    }
+}
+
+