well you asked for a in depth review so here ya go,
The aesthetic of this game is really amazing, feels like the weird art you would see on empty vhs tapes for recording, you could definitely hone in more on that aesthetic with some shaders and still have it not be intense for mobile devices.
The use of the font for menu items and tutorial text though is hard to read and does not fit. it would be much better to use something basic and simple without any weird design choices, those things fit for a title but not for a menu item or text which is meant to be readable over aesthetic.
The tutorial went a little slow and there wasnt really that much to learn that needed so much, with such simple controls and a physics based system though you have a ton of potential for intense depth. When playing against a ai i noticed that the ai player did not budge when i pushed them making the game feel very asymmetrical, when playing with another player though it added more depth and some risk reward play by being able to try to push off the other player but still worrying about the obstacles. This could be really really really fun if you capitalized on these aspects of the game more and maybe even in impossible mode had a ai player next to you who you could try to bump off
I noticed that the levels in impossible were random, if it is meant for the competitive community this is not going to sit well since they will want fixed situations to compare against each other. If you want to keep random level generation consider using a seed, that way you can have infinite levels but still have them be the same for whoever uses the same seed.
Whenever the player dies they start at the beginning of the level, this is perfectly alright when you are alone but when theres a enemy or another play this certainly does not sit well. i noticed you do have a speed boost for those who are behind but that does not fix the frustrating feeling of starting from the start, considering ai does not make mistakes and is not bound by the same physics as the player this becomes very frustrating. what you could do is have the player who died spawn a distance away from the leading player. That way they are still close and can catch up, but dying still has a consequence.
As for the actual rolling around it feels perfectly fine on flat surfaces but as soon as they start curving up and down and you have those twisting slopes the physics gets janky and it does not feel right, this is fun if two players are playing but when playing against a perfect ai who cannot make mistakes and cannot even be bumped off it just feels unfair. You could solve this map the physics to a 2D version of the platform and have the image of the player rendered just on the topographically highest surface. You could also solve it by having the players movement based on rotation instead of just offsetting the balls velocity left and right, this way movement also has a tradeoff where rotating means less speed forward. this would create even more depth and you could have a super interesting experience on your hands.
overall it was a pretty ok game but there is SO MUCH MORE you can do with this and i hope you do! i will be following and looking forward to your future releases so please keep at it. <3