The band, fronted by Alexia Rodriquez who does clean vocals and their unclean vocalist Cisko Miranda who also does cleans sometimes, have a model for most of their songs. It's usually unclean verses, clean choruses. While there is some change, that's usually how their songs go.
On Masks there is little to no change. While there are some songs that stick out, most of the songs all sound the same. This is not to say that the songs are bad. They're all good but only a few of them stick out.
"Lost and Forgotten," "Where I Want to Be," "Surface," Little Liar," "The New Plague," Infected," "The Secrets Between" and "The Forbidden Line" all stand out and are catchy. They stand out around this sea of clean choruses and breakdowns.
"The Secrets Between" and "Where I Want to Be" are both previously on their last album, 2011's White Lotus. That is where the band make a mistake; putting older, better songs on the album.
While the album isn't the best thing that Eyes Set to Kill have done, it is a great record. It leaves behind the acoustic undertones of their previous album for 13 songs of straight aggression and heaviness. Eyes Set to Kill for all of their flaws are still a great band and they continue to make great new albums. Regardless of whether or not a band can go on making the same album five more times, that remains to be seen.