@echo off
:menu
cls
echo 1.Sign in
echo 2.Register
echo 3.Exit
echo.
set /p input=What would you like to do:
if %input%==1 goto log
if %input%==2 goto reg
if %input%==3 goto exit
goto menu
:reg
cls
set /p user=Enter your desired username:
set /p pass="Enter your desired password:
echo %pass% >> %user%.txt
:: This will prompt for a username and password and then
:: output the user variable as the name of a .txt file that contains the
:: password
goto menu2
:log
set /p user="Enter your username: "
set /p pass="Enter your password: "
set /p password=<%user%.txt
pause >nul
:: This will check if the password entered is equal to the password in
:: the .txt file
if %pass% equ %password% goto menu2
goto menu
:menu2
::Enter your script here
The system is much shorter when you get rid of the comments. :)
Later on in your game you could use the same system as used in the :reg label to create a batch file with player stats and maybe an inventory in it such as set /a armor=2 and set /a sword=1 then call on that file when you want to show the player their statistics/inventory. Just an idea... Anyway, hope this helps at least a little bit.