Presently of this writing, I do not own Resistance: Burning Skies, but I do know how the story goes from watching the playthroughs on the YouTube; as for a gaiden game, this didn't match up to the expectations to the previous games.
The story goes with average joe NYC fireman Tom Riley being inadvertently caught in the middle of the Chimeran invasion of the US and becoming an accidental hero in the making within a day or so according to the length of time in the storyline, while concerned fore the safety of his family. Eventuallly he is forced to team up with a group of militamen known as the Minutemen and kicked off to the main plot of stopping a "mad" scientist dabbling with Grey Tech technology to (get ready for spoilers) control the Chimera, basically fighting fire with fire.
Despite how "interesting" the plot goes, to me it is considered to be ham-fisted and over-blown. The reasons listed below:
1). A local fireman suddenly grab the first Chimera gun he lays his own and becoming dosed with the Gordon Freeman effect (ex: an ordinary individual without any combat skills suddenly knows how to fire an alien gun or whatever and doing the impossible).
2). The hero becoming an instant widely known figure in less than a day, and HAS to be him.
3). Consistency in canon. The Minutemen themselves is unlikely to work with the US military and would have been targeted and blacklisted by the Grace Admin given that the government at the time is critical of anyone going against authoritive figures like Alliance for American Autonomy, and there is no wonder that they can be an expy of the "Freedom First" group mentioned in William Dietz's novels; Ellie suddenly knowing too much about Project Abraham and how does she knows about Nathan Hale (he was technically a nobody at the time despite barely known for the hero a month after the end of Fall of Man? Jarrignly is the macguffin plot with Grey Tech: Another spoiler is that Riley and the Minutemen decide to throw Grey Tech away as an unnecessary evil which I find to be the most stupid thing given that humanity is being screwed over and having Grey Tech would have dramatically changed the outcome against the Chimera that was expressed in Retribution and R2, and given humanity a chance to survive. But no, the common man to save the day believed that Grey Tech and the government are evil and better off at conventionally fighting the Chimera the old fashion way in FPS with a hope spot (and we know how THAT end in the next six years from now).
4). Awkward moment when Riley saved Ellie despite he being married for all things, and that didn't expressed about this since (makes you almost wonder there will be tryst ala Pearl Harbor).
5). Lastly is the story of having a human antagonist glossing over the Chimera. I find this unnerving for Dietz to continue this pattern that he written in the novels. "The Gathering Storm" where you have President Grace (no surprise there) trying to make "peace" with the Chimera and a human collaborator working for the Chimera (of all things the aliens would simply nail a human and toss its carcass to the meat grinder and become one of them), and in "A Hole in the Sky" where some asshole decide to rebuild the USA in his own way on a post-apocalyptic hinterland while screwing over the other humans rather than fighting the aliens.