I mean sure, it's obviously not an accurate depiction of the Battle of Alesia, but what about the fighting itself?
What do the sources say about Romans and Gauls fighting in the style depicted?
Here's a video of the battle from the show [starts at 1:00, ends at 2:41, 101 seconds total]. I hope this helps commenters in writing their answers.
The Romans appear to be fighting as a maniple which allows three ranks of soldiers that can fall back thru the ones behind them and regroup. Weapons are gladius and scutum. The big guy that broke ranks for melee fighting would be outside of doctrine.