Just to be perfectly clear, this is not something that's entirely Square's fault. Even god-damn Portal is guilty of keeping the main gimmick away from you for way too long (it's not really that long, objectively, but it's a good chunk of the entire two hours you get with the main game).
Yeah, you heard me. Portal has a flaw. Wrap your brains around that, entire game-criticism industry.
Keeping the gimmick of the game out of the player's hands is not automatically a flaw.
I've played Portal like everyone else and it didn't bug me that I had to earn it.
Jedi Knight 2 made me jump through incredible hoops and play through 6 levels of the worst fucking FPS shooter ever made and THEN go through the stupid Jedi powers tutorial before I got to be a Jedi with a plasma stick.
Kingdom Hearts 2 made me shit on myself and then eat the shit that was mixed in with Roxas's shit and then kill several puppies before I got to have fun.
Portal made me... shit, I don't even remember. Run through a few rooms. If I can't remember being annoyed, then it wasn't annoying. Granted, if I played the game again I'd probably want to skip right to the full shebang, but yeah. I wasn't NOT having fun, and that's really what counts.
Also, Portal is more like 3-5 hours, and you don't have the entire gun for maybe 30-45 minutes. At most. I remember getting it in maybe 15.
Unless you take fucking forever to figure out the initial rooms and then blaze through the rest of the game, I guess.