An animated portcullis using objects, curves, hooks, and a single driver controlling it.
Pulleys and such can be easily relocated to fit your scene.
No materials, but each object is UV mapped for tiled textures. All items are named, and are enclosed in a single group.
A slightly different version can be seen here - https://www.youtube.com/watch?v=idokqfs-Cms
Seeing people verify levels like Aeternus makes me realize I'm not even playing the same game. Geometry Dash at the top level is essentially superhuman.
Impressive attention to detail. Nice job!