The protagonist is the only one alive on a spaceship which has taken a beating after a battle with an alien ship, and is radioing to you, the player, for help. Specifically, the protagonist wants you to help him get the ship back in order before the next attack comes along. The signal isn't very good, though, and the protagonist is less than fully coherent, so ascertaining what's going on (or has gone on) secondhand is something of a challenge. (Particularly because all of the standard system commands--QUIT, SAVE, UNDO, the whole lot of them) are disabled--the better to reproduce the sense of actually communicating with someone, of course.) It's an interesting challenge, though--reconstructing past events (for purposes of gaining insight into a present situation) is an underused and potentially fruitful IF technique.
As it happens, though, that's not the focus of what goes on here--there are a few puzzles, and then you reach one of a variety of endings. The puzzles aren't especially good; one amounts to trial and error (made all the more irritating by the absence of UNDO), and another is hindered by some thoroughly unhelpful syntax. (Yes, admittedly, a person is not a parser, and it's not entirely realistic to expect a person's comprehension to work the same way as a parser, but guess-the-syntax is guess-the-syntax.) The endings are good--thought-provoking and well worth reaching--but the puzzles, to my mind, don't fit.
Here, it seems, you have a premise that makes the interactive hook, in the form of puzzles, largely unnecessary. The *game* is a puzzle in itself; you' re trying to figure out what exactly happened, and you're battling the protagonist's vagueness and confusion and the chaos inherent in a partly wrecked ship. The nasty/strange/welcome surprises that you come across should be able to tell the story and keep the player involved all by themselves, particularly when the game is this small. (Well, okay, it would probably have to be a little larger if there were no puzzles.) There's also room for more story development in the distance between player and protagonist: do they trust each other? What do each of them know that the other doesn't? (FailSafe does hit that angle at one point, but there's more that could be done with it.)
Unnecessary puzzles aside, though, FailSafe has its moments. One particularly effective touch is a series of messages that the player receives from a computer analyzing what's happened and who was aboard the damaged ship, messages that the protagonist doesn't receive; the juxtaposition between the player's semicoherent account and the computer's records is occasionally chilling. The inadequate descriptions are part of what makes the game compelling--when several turns of static pass before the protagonist's voice returns, there's genuine suspense. There are also some nicely done red herrings--while there isn't as much exploration potential as there might be, there's enough to keep the game from feeling like a small set of puzzles. And the endings are genuinely surprising (though spoiled somewhat by the game's XYZZY award nomination; don't read the nominee list before you play the game), and force the player to rethink what's come before.
FailSafe's small size works against it, I found--there's too little there for the player to be really pulled up short by any surprising turns. (The player doesn't spend long enough interacting with the protagonist, and getting a mental picture of the story, to be truly caught off guard by unexpected events; the assumptions and mental pictures aren't around long enough to cause much surprise when they're challenged or disproved.) Still, it's got an intriguing premise and it's creatively done, and its spin on the player-PC relationship makes it a must-play for IF theorists.