Reacts as critic gets upset about hotel features (15)
I believe the answer is:
characteristics
'features' is the definition.
('characteristic' can be a synonym of 'feature')
'reacts as critic gets upset about hotel' is the wordplay.
'gets upset' indicates an anagram (I've seen 'getting upset' mean this).
'about' is an insertion indicator.
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'reacts'+'as'+'critic'='reactsascritic'
'reactsascritic' is an anagram of 'caracteristics'.
'caracteristics' going around 'h' is 'CHARACTERISTICS'.
(Other definitions for characteristics that I've seen before include "Parts" , "marks" , "features" .)