first off - that video is from the ascension patch - late 2013, before wreckage, bunker, Predator, incinerator, either one of the G2 mechs, any of the co-op modes, the February patch, and the steam release. this is also when MTR/ADH were still a thing.
Second - merl's video does cover some of the basics of reaper, but in the sense of any other mech - landing your shots is paramount more so with reaper, but still applies with anything else as well. what the reaper really shines at is positioning. it's fuel tank is the second smallest of A's, but has the highest fuel regen rate. This means that setting up a flanking run - remaining just on the outside of the main fight, helping teammates seal the deal on those kills, or punishing the enemy for trying to start a flank themselves - is very easy to do. I would even go so far as to say that a pilot utilizing this aspect of the reaper should almost appear to be in many different places at once.
the reaper's ability - precision overdrive - is.. well.. ..kind of "meh". it basically reduces any and all spread any of your weapons have, regardless of being scoped in or not, which might be useful in short to mid range combat. then again, an enemy will think that closing the gap is going to be the right direction to go in killing you (which it is), and at that point, the spread on the sabot is negligible due to your target appearing to be much larger than your reticle. 6 of one, half-dozen of the other. I dunno.
the reaper is in a so-so state, with practice, it can be a formidable mech, capable of assassinating a large number of targets of opportunity and applying a great deal of pressure to the enemy, and the concievable ability to hold its own in cqc - something that most pilots would take for granted.
TL;DR : with reaper - land your shots, reposition quickly and often with intent to harass and apply pressure, land your shots, don't be afraid to work on that cqc(cuz reaper can be good at it), land your shots, and get used to having an ability that really isn't that much of an ability. And land your shots.
also, her'es a great place to really sink your teeth into all things hawken -> https://community.pl...-guides-hawken/
Silverfire has done a great job of putting this stuff all in one spot.