At the risk of turning this into a wall of text, here's a few other points.
I can't figure out why, but my crits are occasionally doing on the order of twice as much damage as normal, resulting in me sometimes hitting enemies for upwards of 410 damage when I should be doing around 200 with my heaviest hitting crit. (EDIT: On closer inspection, this seems to happen when I hit more than one enemy with the same crit attack. The first enemy takes normal damage, but every hit after that sometimes multiplies. Maybe the attack is somehow critting twice?)
The experience curve doesn't seem to scale as hard as it probably should. I began the fourth planet at around level 70, and am currently 86 and counting, gaining sometimes two to three levels per area. I'm all for not having to grind too much to progress, but this feels like I'm quickly going to run out of upgrades to get.
Some capstones feel like they do practically nothing, I can make a list if you like, while others are downright build-defining, with no seeming differentiation between the two (often sharing the same tier of upgrade).
Blackhole Gullet, for example, doesn't really see use in my builds because there simply aren't enough enemies in any level for its flat increase to actually do anything. Internal Massage is quite simply outperformed by the existence of the Absorption stat.
Then there's Peristaltic Action and Pre-Digestive Enzymes, both of which have *enormous* impact even if you aren't actively building for the stats they scale on.
I enjoy the idea of mutually exclusive capstone upgrades, but the two Paths are the only such example in the entire tree, and the difference that they make is remarkably unimpactful for requiring what should be such a definitive choice. I understand it wouldn't be viable to make such an early decision have any more impact than that (even raising it to 10% XP would be too much for the very first capstone). Maybe it could be combined to a single capstone that gives 5% XP across the board, or maybe each one could have very small increases to the stats relating to each playstyle. If it's not going to matter as a choice, I'd rather not have to make it.