diff --git a/itchiodl/game.py b/itchiodl/game.py
index e0805c5..54206ad 100644
--- a/itchiodl/game.py
+++ b/itchiodl/game.py
@@ -3,6 +3,8 @@ import requests
 import json
 import os
 import urllib
+import datetime
+import shutil
 
 
 import itchiodl.utils
@@ -35,9 +37,11 @@ class Game:
             self.downloads.append(d)
 
     def download(self, token, platform):
-        if os.path.exists(f"{self.publisher_slug}/{self.game_slug}.json"):
-            print(f"Skipping Game {self.name}")
-            return
+        print("Downloading", self.name)
+
+        # if os.path.exists(f"{self.publisher_slug}/{self.game_slug}.json"):
+        #    print(f"Skipping Game {self.name}")
+        #    return
 
         self.load_downloads(token)
 
@@ -51,31 +55,79 @@ class Game:
             if platform is not None and d["traits"] and f"p_{platform}" not in d["traits"]:
                 print(f"Skipping {self.name} for platform {d['traits']}")
                 continue
+            self.do_download(d, token)
 
-            file = itchiodl.utils.clean_path(
-                d['filename'] or d['display_name'] or d['id'])
-            path = f"{self.publisher_slug}/{self.game_slug}"
-            if os.path.exists(f"{path}/{file}"):
-                print(f"Skipping {path}/{file}")
-                continue
+        with open(f"{self.publisher_slug}/{self.game_slug}.json", "w") as f:
+            json.dump({
+                "name": self.name,
+                "dl_version": 2,
+                "publisher": self.publisher,
+                "link": self.link,
+                "itch_id": self.id,
+                "game_id": self.game_id,
+                "itch_data": self.data,
+            }, f)
 
-            # Get UUID
-            r = requests.post(
-                f"https://api.itch.io/games/{self.game_id}/download-sessions",
-                headers={
-                    "Authorization": token})
-            j = r.json()
+    def do_download(self, d, token):
+        print(f"Downloading {d['filename']}")
 
-            # Download
-            url = f"https://api.itch.io/uploads/{d['id']}/download?api_key={token}&download_key_id={self.id}&uuid={j['uuid']}"
-            # response_code = urllib.request.urlopen(url).getcode()
-            try:
-                itchiodl.utils.download(url, path, self.name, file)
-            except itchiodl.utils.NoDownloadError as e:
-                print("Http response is not a download, skipping")
+        file = itchiodl.utils.clean_path(
+            d['filename'] or d['display_name'] or d['id'])
+        path = itchiodl.utils.clean_path(
+            f"{self.publisher_slug}/{self.game_slug}")
 
-                with open('errors.txt', 'a') as f:
-                    f.write(f""" Cannot download game/asset: {self.game_slug}
+        if os.path.exists(f"{path}/{file}"):
+            print(f"File Already Exists! {file}")
+            if os.path.exists(f"{path}/{file}.md5"):
+
+                with open(f"{path}/{file}.md5", "r") as f:
+                    md5 = f.read().strip()
+
+                    if md5 == d["md5_hash"]:
+                        print(f"Skipping {self.name} - {file}")
+                        return
+                    else:
+                        print(f"MD5 Mismatch! {file}")
+            else:
+                md5 = itchiodl.utils.md5sum(f"{path}/{file}")
+                if md5 == d["md5_hash"]:
+                    print(f"Skipping {self.name} - {file}")
+
+                    # Create checksum file
+                    with open(f"{path}/{file}.md5", "w") as f:
+                        f.write(d["md5_hash"])
+                    return
+                else:  # Old Download or corrupted file?
+                    corrupted = False
+                    if corrupted:
+                        os.remove(f"{path}/{file}")
+                        return
+
+            if not os.path.exists(f"{path}/old"):
+                os.mkdir(f"{path}/old")
+
+            print(f"Moving {file} to old/")
+            timestamp = datetime.datetime.now().strftime('%Y-%m-%d')
+            print(timestamp)
+            shutil.move(f"{path}/{file}", f"{path}/old/{timestamp}-{file}")
+
+        # Get UUID
+        r = requests.post(
+            f"https://api.itch.io/games/{self.game_id}/download-sessions",
+            headers={
+                "Authorization": token})
+        j = r.json()
+
+        # Download
+        url = f"https://api.itch.io/uploads/{d['id']}/download?api_key={token}&download_key_id={self.id}&uuid={j['uuid']}"
+        # response_code = urllib.request.urlopen(url).getcode()
+        try:
+            itchiodl.utils.download(url, path, self.name, file)
+        except itchiodl.utils.NoDownloadError as e:
+            print("Http response is not a download, skipping")
+
+            with open('errors.txt', 'a') as f:
+                f.write(f""" Cannot download game/asset: {self.game_slug}
                     Publisher Name: {self.publisher_slug}
                     Path: {path}
                     File: {file}
@@ -84,12 +136,12 @@ class Game:
                     This game/asset has been skipped please download manually
                     ---------------------------------------------------------\n """)
 
-                continue
-            except urllib.error.HTTPError as e:
-                print("This one has broken due to an HTTP error!!")
+            return
+        except urllib.error.HTTPError as e:
+            print("This one has broken due to an HTTP error!!")
 
-                with open('errors.txt', 'a') as f:
-                    f.write(f""" Cannot download game/asset: {self.game_slug}
+            with open('errors.txt', 'a') as f:
+                f.write(f""" Cannot download game/asset: {self.game_slug}
                     Publisher Name: {self.publisher_slug}
                     Path: {path}
                     File: {file}
@@ -99,14 +151,13 @@ class Game:
                     This game/asset has been skipped please download manually
                     ---------------------------------------------------------\n """)
 
-                continue
+            return
 
-        with open(f"{self.publisher_slug}/{self.game_slug}.json", "w") as f:
-            json.dump({
-                "name": self.name,
-                "publisher": self.publisher,
-                "link": self.link,
-                "itch_id": self.id,
-                "game_id": self.game_id,
-                "itch_data": self.data,
-            }, f)
+        # Verify
+        if itchiodl.utils.md5sum(f"{path}/{file}") != d["md5_hash"]:
+            print(f"Failed to verify {file}")
+            return
+
+        # Create checksum file
+        with open(f"{path}/{file}.md5", "w") as f:
+            f.write(d["md5_hash"])
diff --git a/itchiodl/utils.py b/itchiodl/utils.py
index 1afd543..1918648 100644
--- a/itchiodl/utils.py
+++ b/itchiodl/utils.py
@@ -2,6 +2,7 @@ import requests
 import re
 import os
 import sys
+import hashlib
 
 from clint.textui import progress
 
@@ -54,3 +55,12 @@ def clean_path(path):
         path_clean = re.replace(r'[\<\>\:\"\/\\\|\?\*]', "-", path)
         return path_clean
     return path
+
+
+def md5sum(path):
+    """Returns the md5sum of a file"""
+    md5 = hashlib.md5()
+    with open(path, "rb") as f:
+        for chunk in iter(lambda: f.read(4096), b""):
+            md5.update(chunk)
+    return md5.hexdigest()
diff --git a/upgrade_tree.sh b/upgrade_tree.sh
new file mode 100755
index 0000000..5610dfa
--- /dev/null
+++ b/upgrade_tree.sh
@@ -0,0 +1,5 @@
+#! /bin/sh
+
+find $1 -maxdepth 3  -mindepth 3 -type f -print0 | while IFS= read -r -d '' f; do
+    md5sum "$f" | cut -d ' ' -f 1 >> "$f.md5";
+done
\ No newline at end of file