The album reached No. 32 on the Billboard Heatseekers chart and No. 35 on the Top Independent Albums chart. "Love?" became the album's single and had a music video which aired on Headbanger's Ball. The video (a tribute to the movie The Evil Dead) depicts the band performing in a haunted cabin in the woods.
Townsend and Hoglan were the primary writers of the album, since Simon and Stroud were busy with other commitments. To prepare for the recording of Alien, Townsend had stopped taking the medication prescribed to treat his bipolar disorder; he explained that the final track, "Info Dump", is a reflection on the panicked state of mind that ensued when he stopped taking his medication. Townsend has stated that the easiest track to record for the album was "Zen", and the most difficult track to record, "Skeksis", was also his favourite. The making of Alien was documented and made viewable online on Century Media's official site in February 2005. It was also available as a bonus DVD of the limited first edition of the album. The band recorded a cover of Tom Jones's "What's New Pussycat?" that was scheduled to appear on Alien, but it was not recorded entirely because "it did not fit the flow" of the album. The song is not expected to be released anytime, even though Blabbermouth.net has reported so.
Due to some kind of error, the unmastered promotional release of Alien (and subsequently the early leaks of the album on the internet) contained the longer version of "Love?" and a version of "We Ride" which had most of the guitar solos missing. Also, on this promo release the track "Thalamus" was credited as being called "Landscape". Previous to the promotional release, press releases credited "Thalamus" as being called "Mega Bulldozer".
Alien was released on March 22, 2005, selling 3,697 copies in its first week. It reached No. 32 on the Billboard Top Heatseekers chart, and No. 35 on the Top Independent Albums chart. Critics praised Townsend's inventiveness and the dynamism of the songs in which "melody and discord meet midway"; Adrien Begrand of PopMatters wrote "Strapping Young Lad have raised the bar yet again", while Blabbermouth.net's Krista G. called it one of the best albums of the year.
"Love?" was chosen as the sole single from the album. Its accompanying music video, inspired by the cult horror film, The Evil Dead, was directed by Joe Lynch. The video garnered the band wider attention, and helped "Love?" become one of their most recognizable songs. Jed Simon admitted to having produced a video for this particular song because it had "the most commercial potential". "Love?" was originally one of two confirmed songs for an EP that was supposed to contain four new songs and four covers. Although planned for release in 2003, the EP was eventually cancelled. A second music video was released for the track "Zen".