Andi Toma and Jan St. Werner are better placed than most to tackle the uniquely hazardous task of putting out a double album. Mouse on Mars is 21 years old, after all, and so the simply titled 21 Again is a reflection of a hard-won confidence and maturity after more than two decades of making music. During that time, the pair has covered a lot of ground; each Mouse on Mars album has seen the duo explore and absorb a diffuse array of styles and influences that, while mostly electronic by definition, have delved into the outer reaches of post-rock, hip-hop, R&B, noise, and ambient music.

21 Again is a bit different. Aside from its 30-track largesse, what sets the new album apart from previous Mouse on Mars LPs is its number of collaborators: there are nearly 40 bands, DJs, producers, and vocalists who contribute in some manner to this sprawling collection. On paper, this is a terrible idea; no matter how esteemed its members, an album-by-committee seldom produces inspired results. When this approach is transposed onto a double album, a distended, by-the-numbers mess is usually the outcome.

The first disc, sadly, follows the script somewhat—but it’s not without its good moments. After a rambling happy birthday message from Eleni Poulou and Mark E. Smith, “Fertilized” launches 21 Again with a snappy disco-funk record that sees Cavern of Anti-Matter (a project featuring Stereolab’s Tim Gane) and Mouse on Mars do a pretty good Siriusmo impression (he, incidentally, lends a hand to “Immer Kurz Davor,” a typically weird, Vaudevillian take on glitchy hip-hop).

“Errormom,” featuring Errorsmith, kicks off a small purple patch on the first disc with a sketch-like track of detuned snares and clipped drum sounds, while Eric D. Clark‘s vocal on “Lost and Found” anchors a jaunty, synth-splashed electro-pop track. Up next is “Purple Fog,” featuring Modeselektor and rapper Mr. Maloke, which brings an abrupt end to the purple stretch with its fate-tempting title. It’s a gaudy hip-hop party track that splices together bubbling kuduro rhythms and a stiff, three-note chord that sounds cartoonish, but not all that much fun.

Towards the end of the decidedly uneven first disc, Atomâ„¢ contributes one of the highlights of the whole double album with the echo chamber pads and automated voice of “Key My Brain,” which is followed by an excellent one-two of introspective electronic pop from vocalists Helado Negro (“Carca Jadas”) and Laetitia Sadier (“My Toe Is on Fire”). It’s these three songs especially that make the first disc a worthwhile part of 21 Again.

The second disc, however, is a very different animal. Its approach is roughly the same as its predecessor, but somehow it sounds much more like a Mouse on Mars album, and its collaborators seem to be a better fit. Having seemingly purged the fitful bouts of excess from disc one, the other half of 21 Again finds Mouse on Mars getting a firmer grip on quality control.

“Putty Tart” is a Junior Boys-assisted R&B jam with an abundance of laser-precise melodies and a butter-smooth vocal (“Splymogym,” its cousin on the other disc, becomes too saccharine once Scratch Pet Land‘s over-processed vocal announces itself), and the following track, “Metalonna Swamp,” is a moreish jumble of silly noodling synths and folky banjo melodies that sound as fun and chaotic as a beerhall conga on the last day of Oktoberfest.

The rest of disc two takes on a pricklier character, twining Mouse on Mars’ unruly melodies with knotty, bass-heavy IDM beats, and it’s where 21 Again really settles into itself. Funkstorung‘s and Mouse on Mars’ “Bon Djerry” is among the best of these; crunchy, foil-coated drums splutter and spin over a track that, at first, gives off the warmth of an early morning sunrise, and then flickers into life as a fire-breathing, main-stage-slaying club banger.

At the end of it all, 21 Again really is exactly like a 21st birthday party: it’s rowdy, crammed with guests, and mostly a lot of fun. It’s also pretty drunk on itself, and at a party full of pissed-up revellers, there will always be a few people who overstay their welcome, as some of these tracks certainly do. A more intimate celebration with a shorter guestlist would have made for a better LP, but those willing to forgive 21 Again‘s periods of over-exuberance will still have a pretty good time.