static_aabb2d_index VS Fyrox

Depending on your use case this crate provides a very fast static (must be rebuilt to add/remove bounding boxes) axis aligned bounding box index: https://github.com/jbuckmccready/static_aabb2d_index. It's very fast to build the index using hilbert curve sorting and forms the index structure as a tree with controllable node sizes.

Here is the approach ported to rust code for a 2D spatial index: https://github.com/jbuckmccready/static_aabb2d_index/blob/master/src/static_aabb2d_index.rs#L411

Some other Rust game engines ship with their own physics engine. Fyrox, for example, has advanced 2D/3D physics, supporting rigid bodies, joints, ray casting and more. Godot too, which has community-led Rust bindings also has an in-built physics engine as well as a Godot-native extension using the Jolt physics engine. In fact, which is reported to be more performant than the official physics engine.

checkout https://fyrox.rs

I would say Bevy isn't really similar to Unity. Something like Fyrox - https://fyrox.rs/ - would be more similar. Bevy is more low level and lacks an editor (as of now, it's planned)

Fyrox might be an option, but for what you're looking (simple game logic, low performance concerns, desire for complete editor) for I'd probably choose Godot over it.

Besides Bevy there’s also Fyrox Engine that looks very promising. https://fyrox.rs/

We have our own engine. There aren't really full engines available in the Rust ecosystem. Bevy attempts to fill this, but it's far from being feature complete. There's also https://fyrox.rs/, but that's also work in progress. There's also https://rend3.rs/ which is just a 3d renderer, so you'll need to build the rest of the engine yourself.