Zeus’ debut owes part of its existence to Jason Collett, the Canadian roots rocker (and former Broken Social Scene member) who employed Zeus’ two co-founders for years in his backing band. A number of veteran power pop groups also deserve some credit, however, as Say Us re-creates the sunny strains of Sloan, the Hollies, and the Beatles to charming effect. Like those three groups, Zeus doesn’t have a dedicated lead singer; songwriters Mike O’Brien, Carlin Nicholson, and Neil Quinn all share that role, and they switch instruments with equal frequency. The result is an album relatively devoid of patterns, since no single musician remains with one instrument long enough to repeat the same trick twice. Zeus’ retro state of mind remains consistent, though, and the band fills Say Us with vocal harmonies, vintage guitar jangle, and riffs culled from a lifetime of classic rock fandom. It’s part British Invasion throwback and part 21st century indie rock, with a hint of heartland twang -- these guys played with Jason Collett, after all -- tying the package together.