Structure I has lost the lintel over its central doorway as well as much of its roof. These missing parts represented the monster's upper jaw and teeth and its forehead. The two eyes are still intact and frame the upper part of the doorway. This makes it visually hard to recognize it as a zoomorphic entrance.
"For the rest, the doorway as such seems to have been a more orthodox and common version than that of Structure 2, and in regard to its volume composition and general design, this building falls more clearly within a series of Chenes regional tendencies that include, among other characteristic elements, a notable vertical frieze set off at the corners by an enlargement that, together with the middle and upper moldings, gives this frieze the very special appearance of a panel (a trait that, even thought it is used in a more systematic way in the Chenes region, appears in some notably contemporaneous buildings of the Rio Bec region, as on the wings of Structure II at Chicanna or the stylized huts on Structure 1 at Peshal)."
Paul Gendrop, "Rio Bec, Chenes, and Puuc Styles in Maya Architecture", p.102.
"On Structure 1 of the same city of Hochob more or less contemporaneous with Structure 2 these cascades of masks are an interesting compromise between the profile and corner variations, because even though they are essentially profile versions, they could be called "three dimensional" because of the marked break between the central entrance and the wings, and, above all, because of the effect of the noses, standing out in three dimensions over thier smooth lower walls. "
Paul Gendrop, "Rio Bec, Chenes, and Puuc Styles in Maya Architecture", p.101-2.
The stair leading to the entrance to this temple represents the monster mouth lower jaw. A magnificent array of curved fangs defines the lower side of this platform.
Below is Paul Gendrop's attempted reconstruction of Structure I:
Paul Gendrop, Rio Bec, CHenes, and Puuc Styles in Maya Architecture, fig. 74 on page 102.
Structure V is part of a larger architectural complex which includes Structure VI and possibly a no-longer-existant Structure VII, all of which were connected by a low range of rooms running east-west along the north side of the plaza.
Similar complexes are common at other Rio Bec and Chennes sites. At Dzibilnocac, a similar complex shows a long horizontal building crowned on each end and in the middle with small pyramids topped by semi-functional temples.
All of the buildings which are elements of the south side plaza complex (Str V, VI and possibly a no-longer-existing Str VII) consisted of a small pyramid topped by a semi-functional temple with a roof comb.