Sonic Superstars is the most recent 2d Sonic game this year, and I will admit I had a pretty good time with this game and it's new mechanics. However, like most sonic games with new stuff there's a few flaws.

Graphics wise it does look good, even on the switch port the game runs well with only some downgrade from the PS5 version. 
Sound wise I agree this is one of the most forgettable sound tracks in the series, but to be fair after sonic frontier's boss music it would be difficult to top that, but even from the view point of a 2d classic sonic it really is in one ear and out the other. Story wise is non existent as the game doesn't tell you what exactly is going on (not even the game box describes much). Even if classic sonic games have also done this it never has been good story telling if you have to research outside sources to understand the plot of the game. All I can guess is Eggman is using this island with giant critters to power bigger badnicks, and hired Fang with his new partner Trip to beat Sonic, though later Trip turns to your side and is revealed to be a dragon, and apparently there's an evil dragon sealed in a stone that kinda just pops out after beating Eggman (He didn't even take the stone for his own purposes. The dragon just shows up in the last story).

Gameplay wise it's classic sonic, but with access to 4 other characters: Tails, Knuckles, Amy, and Trip our new character. Each character has some exclusive abilities: Sonic has the landing dash, Tails can fly for a while, Amy has a double jump and her hammer can punch through spiked enemies during the 2nd jump plus holding the jump button after the 2nd jump will have her hammering away while running, knuckles can climb walls and glide, and Trip can double jump with her 2nd jump allowing her to climb on walls and ceilings. What's the same between all 5 is their speed so they can be used for local multiplayer, and the chaos emerald powers. Getting the chaos emeralds is pretty easy as u just have to find the big ring in certain stages to get each emerald and swing around the stage to get the emerald. each Emerald gives you a power you can use once between each check point varying from very useful to situational at best. Also if you reach a check point with 50 rings you can enter a bonus stage to get 3 medals. After you get all 7 emeralds you unlock super powers for all 5, but only Sonic and Trip have super forms (with Trip becoming a badass golden fire breathing dragon). The main complaint with this game is the bosses, most of them are bad because they waste so much time just to hit them with the final bosses being the most tedious and time consuming to take down.

There's also an online mode where you can battle or time attack a few players for fun for medals and rank. It's a fun short romp to play online, especially as you get to play as your own metal character you assemble with medals used to purchase parts and paint (One complaint I have is paints and patterns are one time use items instead of permanent unlocks, and patterns can be expensive).