Jimmy Fallon’s strong suit has always been his impressions, so the stand-up portion of his premiere comedy album, “The Bathroom Wall,” stands out as the more entertaining half. If the “Troll Doll Jingles” looks or sounds familiar, however, that’s because he did a shorter, cruder version on Saturday Night Live.

Another familiar track is the last one, “Hammertime,” the audio version of Fallon’s tribute to the ’80s, in which he shows that all the songs of the decade of his youth can be set to M.C. Hammer’s “Can’t Touch This.” It worked better when he performed it at the Concert for New York last fall, though the performance went largely unappreciated, except by the following act, Bon Jovi. In one of the best pieces, “Troll Doll Celebrities” (apparently, Fallon has a thing for trolls), he does freakishly dead-on impersonations of Robin Williams, Cliff the mailman from Cheers, Gilbert Gottfried, and Jerry Seinfeld. With the hilarious “Chris Rock is my R.A.” it is hard to believe it is Fallon, not Rock, ranting. The rest of the stand-up is tepid at best, even though the brunt of it is about the hell that is college life.

As far as the music goes, Fallon offers a mixed bag of songs that are meant to be funny, ironic, satirical SNL-esque tracks. Sometimes it works. Mostly it doesn’t. The very un-Jimmy falsetto “Idiot Boyfriend,” his first single and first music video for MTV — which is pretty awful, and we’re talking those Bob Dole promoting Viagra commercials awful here — is in fact irritatingly catchy, sort of like the Gilligan’s Island theme song. Of the musical half of the CD, “Boyfriend” is the best of the batch. Then there’s “(I Can’t Play) Basketball,” which I wouldn’t play again myself. It’s a fine idea, mocking the rappers by self-deprecation, but somehow, it, like many of the other songs, just isn’t over-the-top outrageous enough to be a hit — or even successfully comedic. The lyrics are worthy, but his sound is deadpan in extremus.

“Snowball Fight” is an exception, but, as Yogi would say, it’s d*ja-vŸ all over again. Though I can’t swear I heard it on SNL, the familiarity makes it banal. And in the end, that becomes the problem. Those hoping for something new and unique from Fallon will be sorely disappointed because it sounds like one long, sort of subpar SNL sketch that would probably be better to watch than to hear, but not by much. Everything on the album sounds like you’ve heard it before. Still, Fallon is impressive in his range of his abilities. Yes, the boy can sing. And yes, the boy can write. But we knew that all before, and the album just feels dated even though it hasn’t been out for long.

Fallon’s old stuff is good, but it’s still old. His unbelievable impressions redeem the album, and the booklet is actually pretty damn funny. Unfortunately, “The Bathroom Wall” is short on what he does best, not to mention just very short in general (just under 37 minutes). And short, for die-hard Fallon fans, just does not cut it.

P.S. If you buy the album and wonder about the skips between the stand-up bits, don’t worry. Neither the CD nor the player is broken. The annoying transitional scratching is, for an unexplained reason, intentional. Hopefully, he’ll skip the skipping when he comes to Woolsey tonight, or it might indeed be a pretty scary concert.