Words to describe something that does not reach your expectations for it

Solution 1:

An epigone. IPA: ˈɛpɨɡəʊn Greek: ἐπίγονοι

Epigone means a pathetic copy, a derivative, a completely un-memorable also-ran, created by the half-hearted effort of a talentless hack, who probably would never have had the idea to create the derivative work, if he had not admired the original. If "paragon" is the greatest exemplar of a particular platonic ideal, then the "epigone" is a shallow pale photocopy. The greek root of the word epigone means "born later". Synonyms: Also-Ran, Derivative.

I first saw the word referring to the "epigones of Tolkien"; That mass of drivel that copies Tolkien, poorly.

Solution 2:

a shadow of a park

a semblance of a park

a simulacrum of a park

Solution 3:

'Parody' would be my guess, FWIW.