diff --git a/downloader.pas b/downloader.pas
index 65e3821..b72b7aa 100644
--- a/downloader.pas
+++ b/downloader.pas
@@ -1,13 +1,13 @@
 program downloader;
 
-uses fphttpclient, base64, opensslsockets, fpjson, jsonparser, SysUtils, process, Classes, libtar;
+uses fphttpclient, base64, opensslsockets, fpjson, jsonparser, SysUtils, process, Classes, libtar, CustApp;
 
 var
-  authString: String;
   gameId: Integer;
   gameData: TJSONData;
   client: TFPHTTPClient;
-  tarFile: String;
+  authString, tarFile, errorMsg: String;
+  app: TCustomApplication;
 
 procedure createFileDir(filePath: AnsiString);
 var
@@ -111,10 +111,24 @@ var
   username, password: String;
 
 begin
-  Write('Enter username: ');
-  ReadLn(username);
-  Write('Enter password: ');
-  ReadLn(password);
+  if app.HasOption('u', 'user') then
+  begin
+    username := app.GetOptionValue('u', 'username');
+  end
+  else
+  begin
+    Write('Enter username: ');
+    ReadLn(username);
+  end;
+  if app.HasOption('p', 'password') then
+  begin
+    password := app.GetOptionValue('p', 'password');
+  end
+  else
+  begin
+    Write('Enter password: ');
+    ReadLn(password);
+  end;
   authString := username + ':' + password;
   client.AddHeader('Authorization', 'Basic '+base64.EncodeStringBase64(authString));
   client.AllowRedirect := true;
@@ -127,32 +141,41 @@ begin
 end;
 
 begin
-  if ParamCount > 0 then
+  app := TCustomApplication.Create(nil);
+  errorMsg := app.checkOptions('g:u:p:', 'gameid: username: password:');
+  if (errorMsg = '') then
   begin
-    gameId := StrToInt(ParamStr(1));
-    client := TFPHTTPClient.Create(nil);
-    if authenticate(client) then
+    if app.HasOption('g', 'gameid') then
     begin
-      if getGameData(client, gameId, gameData) then
+      gameId := StrToInt(app.GetOptionValue('g', 'gameid'));
+      client := TFPHTTPClient.Create(nil);
+      if authenticate(client) then
       begin
-        tarFile := downloadGameTar(client, gameId);
-        extractTar(tarFile);
-        DeleteFile(tarFile);
-        WriteLn('Download finished');
+        if getGameData(client, gameId, gameData) then
+        begin
+          tarFile := downloadGameTar(client, gameId);
+          extractTar(tarFile);
+          DeleteFile(tarFile);
+          WriteLn('Download finished');
+        end
+        else
+        begin
+          WriteLn('Invalid game id given');
+        end;
       end
       else
       begin
-        WriteLn('Invalid game id given');
+        WriteLn('Invalid username or password');
       end;
     end
     else
     begin
-      WriteLn('Invalid username or password');
+      WriteLn('No game id was given');
     end;
   end
   else
   begin
-    WriteLn('No game id was given');
+    WriteLn(errorMsg);
   end;
 end.