Been playing an indie title called Freedom Planet.
It's... well, the first thing to think about is that it was pretty much a Genesis Sonic Clone, at least at first glance. A lot of alterations, such as the general lack of contact damage and the lack of a spindash/ball mode for most everyone (most of your damaging options are more akin to a beat-em-up), really change up the flow of gameplay. You'll also note that Rings aren't a thing here. Instead you're working with standard HP. This is a very good thing, because you will get hit. A lot.
Also... Sonic 4 physics. Just... Sonic 4 physics. Though it doesn't really detract from the game.
Stages are fun as all get out. I really, REALLY like the gameplay here. I've heard that the fact that the stages are built to cater to every character causes it to be a bit cluttered, but I didn't notice this while playing.
Soundtrack's just beautiful. I love these songs. So much. And most stages have TWO versions of their song.
In both above categories... I'm pretty sure
Fortune Night is best stage. Everything about it is fun. Easter eggs everywhere, and a really, REALLY cool boss battle.
Voice acting in the game's many, many cutscenes is touchy, at times. Some lines are delivered well, some aren't. Kid-character lines are about as good as they ever are. The voice clips are fine in-game, though.
Really, most issues I've heard of or experienced myself are in the story, which you can choose to skip by playing Classic Mode (as opposed to Adventure Mode).
Aside from the iffy voices, the story likes to jump between fun, hammy, and lighthearted (most of the early stages) to... well... terrifyingly dark (in particular, Lilac's Adventure Mode, Thermal Base, has a rather... unsettling interrogation scene from the already creepy main villain) and it doesn't do the best job of making the transitions. I was okay with it (I personally felt that the VA-work for the mentioned scene was on the right side of the sliding scale of good vs bad), but I've heard that mileage may vary.
If you're willing to risk the above, this game has an interesting world it wants to show its players, and the villain jumps between deliciously genre-savvy and... well... horrifying, in a way that was interesting, at least to my tastes (he's also a SUPERHARD Final Boss. Like... It's not even funny). If not, well, Classic Mode is more than fun enough on its own.
There is also the issue of glitches, though I never experienced them personally.
The only other issue that you might have going in that isn't story-mode exclusive is... well... the bosses are HARD. Painfully hard. BRUTALLY hard. Unless you are playing on Easy Mode, in which they're significantly easier (almost too easy), the bosses after the first few are HAAAAAAAAAARRRRRRRRDDD.
But other than that, most of the game was FUN to play. Just... loads of fun. Costs about 15 bucks for access to the game (and any updates/DLC-type things that come next). I found it to be a WONDERFUL expenditure.