There's some areas in Batman Arkham Asylum where I SHOULD be able to use the grapple like a a ledge of a cliff that obviously needs to be grappled to be reached or opened vent via Batclaw. But for some reason the game won't let me cast grapple on it.
Area that I'm currently stuck is the prison cell where you defeat Harley Quinn when you get the Riddler Trophy, the doors will closed. I blew up the wall inside & I SHOULD be able to grapple up the ledge.
There was also an instance that I couldn't grapple in the vent to get out of the Batcave. (restarting from last checkpoint over 10 times solved this)
How can I resolve/fix this problem? Take note I'm playing the PC version