Press L+X+A (all 3 buttons at held at once) during gameplay. Not while the game is paused, not in the main menu, not in the stage select. Be sure you applied the IPS patch correctly.
The CRC32 after applying the patch should be 6F040068. ZSNES and SNES9X will display the CRC32 value when loading games along with other information.
If your CRC32 value matches and you still can't bring up the menu, check that your controller and all buttons are working properly. And yes it is a *real* hack.