Lots of IF lately is written for competition play and is therefore designed to be completed in two to five hours, and more deserves the name of interactive short story. Aaron Reed's Blue Lacuna triumphantly defies that tradition: Aaron calls it an interactive novel, and that seems entirely fair, because the game contains enough text for several full-length novels and is likely to play over 18-25 hours. The result is that it feels gratifyingly spacious, as less ambitious IF cannot, and there is room for emotional effects to build gradually.
This is a great place to start if you've ever been intrigued by the "novel you can play" promise of interactive fiction but stumped by the puzzles or thwarted by the parser. Blue Lacuna comes with a built-in tutorial introduction; it has an extensively reworked parser that offers friendlier messages than average, and corrects many typos automatically; and it allows much of the navigation and interaction to be done with simple keywords, which it will highlight in the text (unless you don't want the highlighting, in which case it can be turned off). Furthermore, it offers your choice of "story" or "puzzle" modes: both explore essentially the same narrative terrain, but story allows you to do so with less fiddly work, so that you can focus on the events. (Personally, I'm finding I prefer story mode even though I enjoy puzzle games, because this particular tale has enough going for it that I just want to find out what happened.)
For navigation purposes, Blue Lacuna lightens the burden of remembering where everything is: it comes with a sketch map of the main area of the game, and provides a system of movement by landmarks so that the player can wander from place to place without having to remember exactly how he got there.
I'm breaking with my usual tradition by recommending this game before playing it all the way through. I still have some distance to go. But the opening sequences are sufficiently impressive to qualify for a recommendation all on their own. The first chapter is a sort of prologue, establishing your character, but already it allows a great deal of player choice. These choices are not about meaningless kinds of character definition ("should I have blue eyes or brown?") or even RPG-like qualities ("should I be a rogue or a magic-user?") but about important aspects of your background story: what happened to you, why, and what you feel about it. There's quite a bit of latitude to change how all this comes out.
Go on to the second chapter and you'll find yourself in a spacious world to explore -- by modern IF standards, a vast one. The imagery of this world is striking, and it further evolves with the time of day and the variations of the weather, all lovingly simulated. People who enjoyed Worlds Apart will likely find Blue Lacuna very satisfying, because it offers the same extreme attention to the details of a fantastic and visionary landscape.
Blue Lacuna is a finalist in the 2010 Indiecade Festival.