Hey there, I just completed the game (getting Pollinate before Sprout indeed fixed it), so I can confirm now how I got to the west area early, and it's not through the way you mentioned. Basically, I just went back to the starting area, went left and crooked my way up through the wall like this. Using the crook gives you your jump back, so as long as you can grapple onto something, you can scale heights pretty quickly, I didn't even need Fertilize. There may be other places where you can use the crook to get to places early, it's quite powerful.
From reading the other comments, I read other people having a pretty smooth progression, so it sounds to me like there was an "intended" path that I deviated from pretty hard, causing me to spend quite some time getting lost. This is a bit unfortunate. Like I said, I think the open-ended progression is quite cool, but maybe you should wait a little longer before letting go of the player's leash. Anyway, now that I've completed the game, I feel more qualified to leave my overall thoughts. Aside from the bugs and softlocks I mentioned, there's a few other points of criticism, which I'll now rattle off in no specific order:
For as much focus as there was on combat, I found that it wasn't really the most interesting part of the game. It was fun to slide through places and break hearts, but the enemies really only served their purpose as pogo fodder, they weren't that interesting to actually engage in combat. And I love a good pogo, but it made the enemy challenge rooms not that interesting. I think the game could work with more focus on combat, or less focus, but right now, but right now, it's in kind of an awkward middle spot, where I wish there were more platforming challenges since the platforming is clearly the more developed feature in this build.
The grappling was a little clunky. Grappling onto boxes or unsprouted vines took an annoying amount of precision, especially when they were quite close to you. The crook automatically locking on made it a lot more bearable, although when several grapple points were close together, it was still sometimes a bit unclear.
I really appreciated the inclusion of a fast travel system since the world is quite big, but the fact that it was name only made it a bit cumbersome to use, since I never really knew where it would take me. It'd be nice if it highlighted the fast travel point you selected on the map.
And last of all, while all the pixel art is quite solid, the huge upscaled mixels on the Tree made me a bit sad. Luckily it wasn't very present throughout the rest of the game, but it wasn't a strong first impression of otherwise a very graphically solid game.
That's all my nitpicks, everything is just very well executed! Good movement, nice setting, overall nice progression and thematically cohesive set abilities... I really enjoyed this game, but I think with some more polish and testing cycles (if you want to, of course), it could be truly great. Fantastic job, all of you!