Ancient Warfare Answers episode (176): How were Roman marines equipped; how did they fight?

Daniel asks, 'I was curious about Roman marines. I see them depicted in video games the same as a classic 1st century legionary, but with their red clothing and shield swapped out with blue. Did Marines fight, and were they equipped the same as a regular legionary soldier? Did they participate in land battles and were they seen as inferior or superior to the regular army? Did they have the same terms of service as their land bases counterparts? Jasper waxes lyrical about a favourite topic.