"Ana" was the first track written for Immortelle and functioned as the blueprint for the album's broader "sonic universe". The sisters describe the song's structure as a film score for a movie they had not yet made, heavily emphasizing string arrangements and cinematic scope.

"Ana" was lauded as a "timeless song" that successfully encompassed decades of musical evolution within its five-minute runtime. It marked a successful shift into independent creative control, allowing the duo to "reclaim their artistic vision" after their initial debut. By blending cinematic grandeur with modern indie-pop sensibilities, "Ana" remains a standout example of Say Lou Lou’s ability to create atmospheric, multidimensional music. The Concocted Dream of Haze: An interview with Say Lou Lou

The second half of the track escalates with "blazing guitar riffs" and orchestral melodies reminiscent of early 60s John Barry soundtracks and James Bond scores. Thematic Depth and Lyrical Meaning

The lyrics—such as "you’re me and I want to be you"—reflect the sisters' own symbiotic existence and the "push-pull" of their shared creative process.

Reviewers at COOL HUNTING and Vanyaland noted its "scratchy beats" and "90s trip-hop fuzz," comparing the sultry energy to artists like All Saints.