Even if you aren't a fan of this band, these two albums are absolutely undeniable, mostly because Vinnie Vincent was co-writing a lot of the material.
allmusic Wrote:
By 1982's Creatures of the Night, Kiss had finally ditched their plans of becoming "respectable artists" (starting with 1979's Dynasty) and had come to the realization that they were a loud, no-holds-barred heavy metal band. Easily their best since 1977's Love Gun, Creatures of the Night contains very little filler and sounds as if Kiss had been reborn (it also includes one of the heaviest drum sounds ever captured in the studio by any rock band). The band is inspired and enthusiastic throughout, especially on such rockers as the opening title track, "Killer," "War Machine," "Saint and Sinner," and one of their great anthems, "I Love It Loud." Also included is one of Kiss' better ballads, "I Still Love You" (later featured on 1996's Unplugged set), as well as "Rock and Roll Hell," a song written about Ace Frehley, who would soon officially make his resignation from the band public. Guitarist Vinnie Vincent (real name: Vinnie Cusano) handles guitar duties here and was eventually named as Frehley's replacement, playing on the ensuing tour. Although Creatures of the Night deserved to be the album that put Kiss back on top of the charts, it performed below expectations (topping out at number 45), as did its tour. Hence, the album is one of Kiss' most underrated. It didn't take a genius to figure out that the makeup had grown stale and was now getting in the way of their music. The time had finally come for the band to unmask.

allmusic Wrote:
Due to the underachievement of their exceptional 1982 comeback album, Creatures of the Night, Kiss knew the time was right to drop the makeup, so in September 1983 the band shocked their fans by unmasking on MTV. Their first non-makeup album, Lick It Up, followed soon after and successfully re-established the band among the heavy metal masses worldwide. Kiss also reconnected with their stateside fans -- Lick It Up was the band's first record to achieve gold status since 1980's Kiss Unmasked. The album's success was spurred by MTV's repeated airing of the imaginative video for the album's strong title track, and songs such as "Exciter," "Not for the Innocent," "A Million to One," and the rap-rocker "All Hell's Breaking Loose" confirmed that the band was back on the right track. Vinnie Vincent again proved to be a worthy replacement to original guitarist Ace Frehley but would unfortunately leave the band after the completion of the Lick It Up worldwide tour (eventually resurfacing with the Vinnie Vincent Invasion in the late '80s). Lick It Up is undoubtedly Kiss' best non-makeup album.