Hey, I'm here to do my part and help you with a review, so here are my first impressions. Bear in mind that I'm playing on my computer, using google chrome.
I'll be kind of harsh, but please know that everything I'm saying here is so you can improve and make better games. My only intention here is to help you improve.
Screen: This is obviously kind of an issue in pc. The screen resolution is clearly designed for smartphones. I'll let this one go in terms of score, but I know this could be fixed relatively easily. Here is an example to check what kind of device is the player using: https://answers.unity.com/questions/1698508/detect-mobile-client-in-webgl.html
You can play around with resolutions from there.
You could also easily add a fullscreen button to help the game fit better in the screen.
Camera: The camera needs a lot of work. It's rigid and "snappy". I see that you added an anti-clip sort of function so that it doesn't go through obstacles, but it moves so abruptly that I just get confused. The camera should naturally and elastically follow the player (the ball, in this case), so that it feels soft and we can easily follow it's movement. Right now, it's the opposite of that.
Tutorial: There is no real need for a tutorial button. You could have easily put those two levels on the "Story" button. If the problem is stars, you could just increase by 6 every skin requirement.
GUI: It's broken, at least in the main menu, it really is. Just look at this: https://imgur.com/a/WyTgf0r
I honestly don't even know if there is any other button. The rest of the gui seems to be working good, although it's generally ugly. It's pretty easy to make decent gui sprites for unity, you should try!
WAIT, I GOT IT: So the gui blue thing is a slider! It really doesn't look like that. The fact that it took me so long to notice kind of shows that the interface is not intuitive enough.
Options: There are none. I can't mix the sound effects and the music to my likings. I can't even mute the sound.
Gameplay:
- The rocks seem harmless but cause an instant loose. Put some spikes in those rocks to communicate a sense of danger. Maybe make them something else. Right now they don't make a lot of sense. I would also like to see an animation where my ball falls off when it hits an obstacle, or goes "poof!" or something. Something other than just an instant game over screen.
- You support full keyboard controls, but not on the menu. You can move the ball with the arrow keys and jump with space. This is quite confortable, but it gets really anoying because you have to use the mouse to restart the level every time you loose. Maybe let the player restart the level with the R key, or allow us to use spacebar or enter to restart once we loose.
- There is no real point for having a sideways inclination in the track. Since it won't make you fall because the movement axis of the ball seems to be limited to forward only, there is no real danger or challenge in those parts.
- The tunnels are kinda broken. You can climb them, you can skip rocks, you can do all sort of random things. Here is me breaking level 3 as much as I can: https://imgur.com/a/qOoNK6l
All in all: Could be fun, but so far I'm not really enjoying the game. It has the basics going, but really needs some polish.