Maybe it's a straight up DnD board game.
You use the rules as stated in the Essentials, PHB X rules, but the setting is explicitly a board game. I haven't actually played any of the WotC boardgames, but I could imagine this something like Runebound or Descent where the goal of the game and campaign is pretty much spelled out.
The only other thing is that they lied about not doing things outside fantasy; because while steampunk (including Flintlock Fantasy, Gaslamp Horror, etc), sci-fi, modern were done in relation to DnD, they were never done in DnD (though the 3.5 DMG had some rules on modern firearms and lasers).