Scan most reviews of Final Fantasy XIII and you'll find a single accusation binding the lot of them: That Square Enix's action-roleplaying game is stiflingly linear, undeviating for too long, and restrictive to a fault.
GamesRadar: "2D side-scroller levels of linearity."
CVG: "15 hours of dead straight single-path linearity is a little overkill."
1UP: "Chop -- there goes the nonlinearity."
GameSpot: "Exceedingly linear exploration and character progression."
Wired: "Final Fantasy XIII is relentlessly linear."
They're not wrong. The game leads off straight as an arrow, though it opens wide dozens of hours later, with as much to explore and accomplish on your own terms after you've polished off the Big Bad as there was leading up to the main story's frenetic final beats.
But let's talk about those "linear" opening hours, because they're on everyone's lips.
When the game begins, after the pre-rendered intro deposits you on The Hanging Edge inside a kind of electric green shell, your first chance to interact is a battle. Your second is a follow-up battle to the first. And your third? A stroll along a wreckage-littered sky-highway toward...yep, more battles. With rare exception, Final Fantasy XIII's following 25 hours are battles followed by more battles punctuated by non-interactive story exposition. You control the rate of advance by steering your party at or away from enemy mobs, but that's all the control on loan at the outset.
Even classic RPG-like features get the boot in an attempt to excise all gameplay flab.
Towns? You'll encounter several in the game--as detailed as they've ever been--but here you battle through them instead of dropping by during interludes to solicit trite one-liners from wandering folk, or to grab a few winks and heal up at an inn. Shops? Snipped along with the leisure side-trips and melded instead with the save point system. Access a save node in Final Fantasy XIII and you'll have the option to browse themed shops that start with just a few simple items, cycling in more advanced stock as you progress.
Why cut that stuff? Because trawling for shallow chitchat and to identify weapon-armor-item stores is frankly--hands over ears, hardcore fans--down-tempo and disruptive. As well, because Final Fantasy XIII's major narrative plays out over a brief span in story-time. Sandwich an entire world to explore between the major plot beats instead of toward the end and you compromise your ability to establish then maintain brisk pacing.
As such, Final Fantasy XIII looks less like a roleplaying game and more like a battle simulator than any of its predecessors. In fact it probably has more in common with its 'Tactics' series offshoot: Discrete battles linked by automatic narrative development. Instead of turns, the battles play out in real-time, but the basic formula's similar.