Just as a data-point, I think I played four games this evening and got about half way up the area after the forest, including unlocking the teleport to the first camp. On that subject, it'd be nice if the bubble unlocked the teleporter as soon as you reached the camp, in case I want to try the challenge room, so I don't have to worry about losing the bubble. (I don't actually know if you can lose the bubble like that; I didn't try it.)
I found myself mostly sticking to using the basic seeds, I think mostly because I was more comfortable with them. Maybe it'd be a good idea to get a free, automatic use of a seed when you acquire it, just so players can see what they do? (Or in the case of seeds acquired in crystal rooms, after you bounce out the effect activates?) I know there's text describing things, but, for example, the Vert Thorn Seed's particular attack isn't what I was expecting when I used it.
Enemies seem very tenacious, and overall the game feels quite difficult, but I think that's pretty expected since it's more-or-less the first time playing. Still trying to figure out what the "gem economy" is like. I've never had enough to buy anything at the store or to invest at the bank.
Last thing for tonight, I found myself wanting to see a gallery of the seeds I've gotten at least once. I think that would provide a nice sense of meta-progression and accomplishment.