Suffering first of blows during remarkable game (9)
I believe the answer is:
paintball
'game' is the definition.
(I've seen this before)
'suffering first of blows during remarkable' is the wordplay.
'suffering' becomes 'pain' (suffering is pain).
'first of blows' becomes 'b' (1st letter of 'blows').
'during' indicates putting letters inside.
'remarkable' becomes 'tall' (I've seen this before).
'b' placed within 'tall' is 'tball'.
'pain'+'tball'='PAINTBALL'
(Other definitions for paintball that I've seen before include "war game" , "messy game" , "simulated combat" , "Missile used in war games" .)