Definitely a step up from the dumpster fire that was Sonic Forces, but that's a pretty low bar.

Gameplay:
The combat in this game takes absolutely no skill at all. Once you unlock all the skills, you can just turn on autocombo and button mash your way through all the enemies.

Cyloop, which is one of the first skills you get, is the most overpowered ability in the game. Don't have any rings? Just run around in circles with cyloop and you'll have hundreds within seconds and you can boost around the whole map. You can even use it to stunlock enemies mid-combo while you button mash them to death. Even if you don't use auto combo you can still easily just mash one button as long as you still use cyloop. This even works on bosses. You can also use cyloop to farm any resource in the game from anywhere on the map. Dead ass, just run around in circles. I'm not even kidding.

Once you gather all the chaos emeralds, which you have to do multiple times, once for each island, you have to fight that island's Titan as Super Sonic.
You don't even take damage as Super Sonic. You just slowly lose rings over time, which doesn't matter because you can carry hundreds of them, which as I said before, can be gained within seconds just by running around in circles with cyloop before the battle starts.
So basically the only way you can lose to a Titan, which are the strongest enemies in the game, is if you enter the encounter with very few rings. Other than that? Autocombo > cyloop into stunlock > QTE > wait for it to die like with everything else.

Even parrying enemy attacks takes no skill. You don't even have to time it. Just hold the button down and wait for something to hit you and you get to punish the enemy for free. Again, works on bosses.

You also have the Cyber Space stages, which are very short versions of classic levels that are damn near optional. You would only ever really have to do them if you need keys for a chaos emerald. Oh, did I forget to mention that you can also get these keys literally anywhere just by running around in circles with cyloop?

I shit you not, you don't even need to actually play the game to progress through it. There's a fishing minigame with Big the Cat you can play where you gain tokens for catching fish that can all be spent on keys, medallions, skill points, and powerups in almost infinite quantities. You have to spend these tokens to get these items, but within a few minutes you can easily get hundreds of them, and all of the items are cheap.
It costs you 8 purple coins for each attempt, but by the time I started doing this I already had about 500 since they're just laying around in the world. That's right, the key items you need to progress through the game can be farmed with both cyloop and in one braindead minigame. You could literally only do these two things without playing any of the rest of the game, and you'd just have to fight the Titans without playing 99% of all other content to finish it.
A speedrunners wet dream. Fitting for a Sonic game.

Oh, and did I mention that all of these things; skill points, keys, medallions etc., can be gained just by running around in circles with cyloop?
This is the only game I've ever played where you don't have to play it to accomplish anything.

Now I know my description of the gameplay probably makes it sound like the game sucks, but it doesn't. On the contrary, I actually enjoyed it. But it still takes zero skill to do anything in it.


Story:
Nothing special here. Quite repetitive I must say. Sonic has to rescue his friends that are trapped in Cyberspace. To do this, he has to collect and give them medallions that don't actually free them, collect the chaos emeralds and then fight the Titan. Rinse and repeat for each island.
Eggman isn't the main bad guy this time, so there's that, but his weird robot daughter is until she becomes moved by the power of friendship. The open world islands themselves are pretty bland and uninspired with nothing to differentiate them other than their biomes, but they at least have fun little obstacles scattered throughout them.

The soundtrack is on point, as usual. Sonic games are well known for their bangers and there's a bunch of songs you can collect from past games that you can shuffle around.
The original score for Frontiers is basically a Sleeping with Sirens album. I'd recognize Kellin Quinn's girlish voice anywhere.

Overall this is a pretty average game. Enjoyable but not commendable. Worth renting but not buying.