When I clicked on this link I was hoping for an interesting discussion about why Rome features prominently in mobile strategy games, rather than an explanation about Roman military history and its supposed literal applications to modern strategy games- but oh well.
I have to admit, I'm not a fan of this guy's humour and felt it was a bit silly and immature- but maybe i'm the wrong demographic- I'm just a mid-20 something male with an interest in Roman history which is why I clicked the link in the first place. Otherwise it's a good video by other measures.
I do play a lot of strategy games but my knowledge of history has never really been of much use in winning at them- it's more about understanding the game mechanics and knowing how to manipulate the AI. When it comes to besieging castles in Stronghold an effective tactic I found was to spam loads of pikemen and have them chip down a stone wall- not something one would have done in real life! Although I have found that in games such as AOE2, building castles in enemy territory is a great way of securing it- which I suppose is reminiscent of how the Romans secured territory and how the Normans conquered England. It all depends on the game really- You couldn't use the "building castles" strategy in Medieval Total War because all the castle's you could capture were pre-built on the map.
Going back to the video I should point out that Roman forts always had four gates one on each wall, not one. This was even if to place a gate there would be impractical. IIRC, on Hadrian's Wall there's Roman forts were the gate opens out onto sheer vertical drops down a cliff!