Ohohoho... this piece.
The Glissandi ARE difficult, but there are so many pitfalls in this piece, by the time you get to the section with the Glissandi, they seem like a break.
The repeated notes are the deadliest part of the piece, especially if you are playing on a piano that you don't get much rehearsal on.
As for the Glissandi - there are fingerings, but really try a bunch out. Play the initial chord with the left hand, and play the RH gliss at your own time, slowly, quicker, quiet, loud, etc. Find a fingering that doesn't scrape the skin [too much]. I used 2-4 for one of them, 1-3 for most, and I think I ended up using 1-4 for one of them as well.
Don't get too caught up on this part - it's definitely unique in the piano rep; I've not seen more than three or four pieces use double glissandi, and this piece uses it the most extensively.
Be VERY afraid of the repeated notes lol. And for those as well, don't be afraid to let the LH help out with them; you can trade them off and still have the RH snag the upper melodic notes as well. There are so many ways to play this section.
The second last page is insane as well... he makes a giant stretto of the entire piece, with all the glittery effects, crammed together - now that part is hard to make coherent.
If you have specific questions, I'd be glad to help out, because I fondly remember this being one of the toughest pieces I played at University haha.