One of my permanent backlog game ideas is a game titled Horse Horse Horse Horse Horse where you're a horse and you press asdf asdf asdf asdf to run right, and fdsa fdsa fdsa fdsa to run left.
NoisyOwl
This is the level you unlock by 100%ing the game (all seeds, 10-coins, and flagpole tops)
I don't know about the larger trends, but Mario games have always had a lot of them. You fall down a pit and you're dead.
Also it's pretty typical for modern Mario games to have a nice normal difficulty curve, and then if you 100% it you get a final challenge that's just completely outside the bounds of the rest of the game's difficulty. This one was just even nastier than the last several incarnations. I'm not sure what the thinking behind these is, unless it really is "yeah we know you're playing Kaizo hacks."
I forgot about the rotating fire bars because it wasn't in the final checkpoint, and I did each checkpoint on a different session.
Non-binary robots rebelling against the nature of their birth.
I don't really know how Nabbit works, but aren't most of the rooms instant death pits anyway?
I love their choice of fake studio name.
But what if my favorite Sonic game is Sanicball?
Why not loud hooting?
Bugthesda.
Have you seen Backpack Battles? It's an autobattler that's 90% inventory tetris.
I've played way too much of it.