Oh it's definitely beatable, and easier now than it used to be. A lot of it comes down to proper timing and item use. If you don't have a decent supply (or any) of items going in, you're gonna have a bad time. Beyond that, it's about trying to crowd-control before things get too out of hand. If you don't take out early enemies quickly, the situation will rapidly deteriorate into something that may very well be impossible to win. Also, keep in mind that you can disable hypno effects in battle by taking off the ear clips. It's still beatable even with them on, and whether you want to consider this "cheating" is up to you, but it's an option.