Sideshow game's hard mountain to climb after two zeroes (6)
I believe the answer is:
hoopla
'sideshow game's hard' is the definition.
I can't tell whether this defines the answer.
'mountain to climb after two zeroes' is the wordplay.
'mountain' becomes 'alp' (the Alps are a mountain range).
'to climb' shows that the letters should be reversed in order (I've seen 'climbs' mean this).
'after' is a charade indicator (letters next to each other).
'two zeroes' becomes 'hoo' (I can't explain this - if you can you should give a lot more credence to this answer).
'alp' backwards is 'pla'.
'pla' after 'hoo' is 'HOOPLA'.
Can you help me to learn more?
(Other definitions for hoopla that I've seen before include "Fairground throwing game" , "Fair game" , "needless commotion" , "Throwing game where prizes aimed for" , "Fairground game; great excitement" .)