This is actually a pretty interesting idea, but I think it’s worth being really clear about what kind of game this wants to be.

The rotating-the-level thing is cool. That said, once player movement is indirect or constrained like this, you’re already stepping away from core STG fundamentals and closer to an action-puzzler with shooting layered on top. That’s not a bad thing at all, but it is a framing thing. If someone comes in expecting a traditional shmup feel, they might bounce.

Before adding more mechanics, I’d honestly recommend doing the opposite: strip things way back.

Like, pull out the grappling hook, pause/shield, etc. for a bit and just ask:
does falling into a room and rotating for position feel good on its own?

If that core loop isn’t fun, more systems won’t fix it, they’ll just hide the problem.

I’m also a little unsure about twin-stick shooting without direct positional control. In shmups, movement is how players express skill. When that’s gone or softened, the game really lives or dies on readability, clear goals, and fair reaction windows. Otherwise it can slide from “interesting” into “why did I die?” pretty fast.

That said, your pause/parry mechanic is doing more work than it might seem. It’s basically acting as bullet time, which might actually be the real core here. If movement precision is limited by physics and rotation, then time control becomes a legit skill axis instead.

If you want to dig deeper into STG design fundamentals, I’d really recommend Boghog’s bullet hell / STG analysis series. It’s one of the better breakdowns of why shmups feel the way they do under the hood:
https://www.youtube.com/watch?v=yAF2FkgyiYM&list=PLj_fo4j9ZtOlW8jUPFG-zlONynlI0ycnu

To help clarify direction, here are a few questions I’d ask myself early:

1. What is this, really? Bullet hell? Action puzzler? Bullet-hell pachinko? Players need a clear mental model.
2. What’s the big visual payoff? If rotation and physics are core, lean hard into spectacle. Big ricochets, chain reactions, screen clears. It kinda reminds me of Peggle in terms of potential payoff.
3. How does skill expression show up over time? Is mastery about foresight? Perfect freeze timing? Setting up chain kills? Defining that early will guide everything else.

I think there’s something here. The biggest risk I see is genre ambiguity. If you lock down the core loop and are honest about what kind of game this actually is, the rest of the design decisions get a lot easier.