Make sure you're on the most recent game version, if you aren't already. Also make sure you aren't running the game off of an external harddrive or a USB or anything like that.
In terms of grapples, if it helps at all for the left-right one, try not to spam the buttons super fast. You want to go at a rhythm, about 240bpm or so.
Otherwise... we're really not sure what to say. We've been wrestling with the game's node webkit version, trying to find the version that is the most performant, but what works for some is worse for others... really sorry about this, truly.