Hello, everybody. ItsTrollSeason here. So, just about everyone on the Internet has heard of machinima, the genre. Almost everyone has heard of Red vs. Blue. A lot of people have watched it, and plenty of people have heard of Season 9. Everyone that's heard of it, has watched it. This includes me.
Episode 15 in particular includes a Freelancer action sequence, in which UNSC Mother of Invention fires her MAC gun onto an urban skyscraper, thus destroying it. This sequence, while totally cool, is not very well in keeping with the science of the Halo universe.
First off, the UNSC generally avoids firing MAC rounds in-atmosphere, or even into an atmosphere from space. The shock wave from a MAC's sonic boom would likely have burst the eardrums of everyone, soldier and civilian alike, in the city. Secondly, there is no way in hell that the firing of a Magnetic Accelerator Cannon would have only destroyed one building. The kinetic energy of a 600-ton tungsten shell fired at 30,000m/s is INCREDIBLE (270,000,000,000,000 Joules to be specific). It is more than capable of levelling an entire city; the epicenter of the blast would be completely annihilated, a fate far more severe than just shattering the windows and collapsing the building after a minute or so.
Season 9 also features the usage of a MAC to annihilate two Insurrectionist-controlled Longsword interceptors. As was explained on the page dedicated to the MAC, this is a gross misallocation of firepower. As discussed above, the weapon comes down with 270 quadrillion Joules of force. The wiki's page on the MAC gun places the firepower as two and a half times that of the Nagasaki bomb, the Fat Man. Fat Man completely obliterated Nagasaki, just as Little Boy (the less powerful model of bomb) obliterated Hiroshima; this is WAAAY too much firepower to be wasted on two Longswords. (And it would also destroy the city completely...)
So, in conclusion, even though it was totally awesome, Rooster Teeth obviously enjoys spectacular action over actual canon. (Not saying it's a bad thing, just a statement of fact.)