Thanks for trying that out, the only thing I could think of is if you were on a laptop or device with multiple GPUs and it is using the wrong one? Otherwise I'm not too sure. There is some delay between the level transitions while it's loading, but shouldn't be anything that carries over to. We'll be releasing a Windows downloadable build after the jam voting finishes, which should be a smoother experience regardless!
Hope you'll be able to give it a proper shot once we do! Thanks again for your efforts!