Вот так игру запустит.
Код:
echo off
cls
IF EXIST %userprofile%\Documents\"1C SoftClub"\"il-2 sturmovik cliffs of dover"\cache\*.* (
echo Erase now
rem pause
del /Q /F /S %userprofile%"\Documents\1C SoftClub\il-2 sturmovik cliffs of dover\cache\*.*"
) ELSE (
echo No files found or wrong path
echo Start game?
pause
) 

Start "" "steam://rungameid/63950"