Not assault, but dubious consent that may possibly be upsetting for some. Near the start of the film, an alien saves Chris Hemsworth's character's life, so he owes her. She implies that she'd like to have sex with him. He appears reluctant. The next morning, we see him sneaking out of her bed, looking regretful. Her octopus-like tentacle has left marks on his chest. This incident is a one-off joke, not relevant to the wider plot.
A flying motorcycle-like vehicle crashes into walls several times, and finally crashes into the desert. Nobody is hurt. There are several other dangerous driving scenes, no major crashes.