I just played your game, and I think it's an interesting little collection game. I really appreciate that you've got a function menu. I like that pausing takes you back the menu.
LEVELS - For some reason, once I've passed a level once, I cannot replay it. I wanted to go back and see if I could get a higher score. Perhaps on the load screen a simple graphic of score breakdown of items. Some small drops give me a 2 points, some big drops give me 1 point. Bees give me 10 poinst. I never really figured out the exact values of all the various water types. But levels do scale in complexity and you've got them categorized correctly.
UI - I play on PC and not sure what the power button does on the main menu screen. It graphically clicks, but doesn't appear to do anything. I can use the arrow keys to go right and left, but up and down move my page, after a little bit it doesn't bother me, but it's good practice to account for the standard movement keys in your game. Since the bee graphic is my life in a level, I keep thinking that grabbing a bee will give me extra lives. Maybe make "point bee" look different from "lives bee"? To be fair, are pretty easy to hash out in trial and error, and works as a kids game mostly, but kids like to do things over and over again, so again, the levels need to be replayable. But as you make more complicated games, you'll need to develop this skill a bit more on easily saying your goals. It took me about 10 levels to realize under the lock of the next level is a score to unlock. This is more important than it being locked. So maybe make the lock graphic smaller and the "score required to unlock" larger.
SCORES - By all accounts you list required scores to unlock, track score in game, and have a high score listed, but since the levels ends upon getting the desired score, there's not really any point in keep track of the previous level score. Don't get me wrong, you absolutely should keep track of previous level high scores! Just don't force stop the game, that way scores actually matter, if even if they only matter to me the player.
GAMEPLAY - As it is right now, there's not any replay value in the game. I beat a level and move on, and I can't replay previous levels. Maybe think of things you can do to keep people coming back to your game. But I have to say, the say everything scale, it does indeed get harder and harder to beat these levels. Around level 9 though, the bugs and bees start falling at a speed that my plant token can't physically keep up with. The overall speed of the user token needs to be much faster/more responsive, particularly once you get up to level 10 and the enemy movements start chasing me, and being more dynamic. There are numerous occassions where I just physically can't dodge everything on the screen. This brings up another issue of hit box. The hitbox is much larger than the actual graphic, and I personally feel it is critical, the hitbox for these types of dodge games be at the most the graphic size or smaller. It's frustrating knowing i dodged an enemy by 7-8 pixels, but still taking the damage or score effect.
VISUALS - I don't mind the photoshop based graphics, it can be charming. But maybe use a different background than the individual flower of that level. Again, it took me a couple level to figure out that which bugs had which negative effect. So just a quick 1 page index of everything would help keep things running smooth.
Overall, because of the difficulty, It did require much more skill to get through the levels, so that part was fun, and it's really important to know that you have a good grasp of how to scale these things out. I couldn't replay prior levels, so if I wanted to replay say level 12, i had to reset and restart the entire game and get back to that level. I think there's a lot of polishing you can do here, but makes for a fun kids game. I would say the most issues to get this to a fully functioning game are: 1) fixing the local storage so resetting the page doesn't reset progress. 2) Give our player token real-time speed, especially when using the mouse, it's way too slow. 3) Make levels replayable without immediately ending them.