Thanks for such an extensive feedback.
All of the graphics were designed by this team's artist (only binocular is an exception, it's a free asset). 2 fonts are from Adobe on which she has licence, one is Unity's default).
ad 1. At the last minute i decided that branches locking in earlier were too punishing, and I didn't design a way to restart or revert growth so I decided to let player change branches according to the rules you exactly defined. I didn't have time to change hints accordingly.
ad 2. What I intended to leave as a text hint is that overshadowed leafed gather less sun. But also couldn't slip it in, also I was hoping that casted shadows will hit that enough. Those shadows however are also still not as fine-tuned, as I'd like them to be, since those shadows should add up and stack.
ad 2.b The sun bar is something I had a real issue designing because I still don't know how to present it clearly. What I did first was just a bar with scale [0 - currentGoal] but in that case when level requirements go up from say 15units to 18units you would see 15/15 change to 15/18 or 50/50 to 50/60. So basically the bar was always full. What you are seeing now is after a change (that was, again, done at the last minute) which makes the scale of bar go to [previousGoal - currentGoal] so when you hit 15/15 goal what you see next is 0/3 actually, because 15 is new baseline and its only 3 apart from next goal. This is why you may see 0 so often. I thought about extending the bar but I also don't think that would be good solution, because goals goes from 6 to >100. If you have any ideas how to do it better, I'd love to hear them.
ad 3. Heh, yeah... I expected it to be a reflex/action game, but the theme bound it to being more cozy. It's hard to imagine watching a tree grow being so intense, but here you have it ;D. The solution to this I think would be splitting game into 2 game modes, since free play can be really relaxing (I know that from tests of mechanics before game had any levels or goals). I made the levels with goals the main gameplay because i did't want to make 100% idle sandbox game - this wouldn't feel enough game-y to me.
You and other players being stuck at level 8 or so is yet another manifestation of last minute changes. There are 9 levels + one semi-infinte, but it appears I left one value in level design not reevaluated.
Again, thank you, I really appreciate your opinion.