I've always thought that "prepare for titanfall" was a very silly line of dialog—a faux-jargon contrivance thrown together after someone came up with a cool name for a videogame and needed to justify with some turn-of-phrase lore. There's no denying that the Titanfall games are excellent, though: We gave the first an 86/100 review, calling it "the most exciting multiplayer shooter in recent years," and Titanfall 2 fared even better: "A brilliant singleplayer campaign married to inventive, skill-intensive multiplayer."
One knock against Titanfall, at least in the eyes of some, is that it wasn't released on Steam. This was back in 2014, when Electronic Arts was leaning heavily into its Origin service: If you wanted to play its games on PC, you had to do it through Origin. Which was fine, really, but as you can see in this old NeoGAF thread (2014, remember), the "No Steam, no sale" sentiment continued to run strong.
@Klink77 yes it does, we'll miss you :(February 4, 2014
Electronic Arts has changed tack since then, however, and over the past year has finally begun returning its games and its services to Steam. As of today, the original Titanfall is among them: The Titanfall Deluxe Edition, which includes the base game and the Expedition, Frontier's Edge, and IMC Rising DLC packs, is currently available for $10—60 percent off the regular price—until November 25.
Bear in mind that Titanfall is strictly a multiplayer shooter, so how much there is to do will depend on how many other people are in the game, and given its age, there might not be very many. (It's a bit too new to Steam for player counts to register.) If you're looking for something a little more singleplayer oriented, Titanfall 2—which really is great—is also on sale.