Using 'spoil' implies something was expected to bring joy or excitement but didn't because of an action. The leaked game ending really spoiled the experience for players.
Pro Tip 2/3
Emotional Impact
'Spoil' often indicates disappointment or a loss of pleasure from an event or activity. Please don't spoil my mood with bad news right now.
Pro Tip 3/3
Past vs. Future
'Spoil' can refer to ruining current events or those yet to happen. His loud laugh spoiled the tense scene in the movie.