>Hitboxes are broken
Their hitbox doesn't reflect their animation on a lot of their attacks. The most notable is the forward leap they do. It is avoided by either jumping over them, hoping the other frog bodyblocks them (RNG) or getting very lucky and dodging it at range. The frog does a very short upwards ascent during its leap, which actually moves the hitbox up too. So you either have to be jumping over them at the start of it or near the end. If you aren't at the peak of your double jump during the first half of their leap, you can get hit by it despite not actually touching him.
>The arena is actually a dome, not a circle
The invisible arena walls aren't flat walls like a cylinder, they're curved near the top. So if you're trying to double-jump over a leap or tongue near the edge of the arena, you can hit your head on the ceiling. Unlike the Jedi Knight series where they'll let you hang at the ceiling for the duration of your ascent in a double jump, this game will cause you to bounce off the ceiling and get sent straight down.
>Synced unblockables
So unless you're lucky or at range, the only way to avoid the forward leap is to jump over them. The only way to avoid the unblockable bite they do is to dodge on the ground. So this is where RNG comes in and just decides you don't get to kill them. Similar deal with the tongue attack that is only avoided if you jump over it or if you're on the other side of the stage. One move will require a double jump while the other move requires a ground dodge so you're getting hit if they're properly synced. Even if you're staying away from them, the leap can cover most of the arena and the bite can cover 1/3 to 1/2 of the arena. This is why the best strat is to play aggressive and kill one of them as quick as possible because these synced unblockables are what will kill you most of the time no matter how well you're playing. It's basically a race to remove one of the frogs before RNG comes knocking.
>Hitstun can kill you with higher levels of HP
If you dumped your skill points into the survival skill tree and picked up health-upgrades along the way, you can survive some of their "1-shot" moves like the bite or leap, it's only the tongue that is a guaranteed auto-kill. However the hitstun on some of these will lock you down long enough to get hit by the other frog and die. The worst example is if you get hit out of the air. If you're lucky, you'll immediately get thrown to the ground on your back so you can recover off the ground and dodging way from the next incoming attack. The more likely result though is that your character does a stagger animation in the air for ~1.5 seconds as they fall to the ground on their feet, which further extends the duration of the hitstun lockdown.
>The leap aways blind you to the other frog
Once you hit Phase 2, the frog will try to leap away and will usually do the tongue attack. In phase 3, they'll start leaping away more often to prepare for the new leap-slam. The problem here is that they can jump over you and completely fuck with your camera briefly. During this brief second, all you hear is the second Frog preparing an unblockable but you'll have no idea what it is. Is it a forward leap? You better time your jump and not dodge. The big bite? You better not jump because that move has some crazy air tracking.
>Phase 3 makes all but 2 of the attacks unpunishable
Aside from the heightened aggression in Phase 3 with 1 new move, nearly all of their punishable moves get their recovery frames significantly reduced and they'll usually follow those up. The leap? Yeah, they always immediately follow that up now. Waiting for 2 bites? Yeah, RNG can decide they do 4 bites. The only 2 safe moves to punish are the unblockable bite and the vomit puddle. This is why most people die after downing one of the frogs. They'll have spent the past 5+ minutes being trained to react a certain way to specific moves and now you can't.