Cant launch hellfire

just bought diablo 1 from the blizzard sale. i noticed when i launched the game from the bnet client there isnt the new classes as described. when i open the game folder i can see hellfire.exe, i launch it and it has new classes, then the game crashes. why cant i access new classes from the bnet client launch?

There’s a drop down menu above the start button in Diablo that allows you to select Diablo or hellfire. Personally, I only play Hellfire because of added content and some small gameplay improvements.