What are the key differences between playing bridge and spades?

The key differences between playing bridge and spades are in the number of players, the deck of cards used, the bidding process, and the scoring system. Bridge is typically played by four players in partnerships, using a standard 52-card deck, with a complex bidding system and scoring based on achieving specific contract goals. Spades, on the other hand, is played by four players individually or in teams, using a 52-card deck with a simpler bidding process and scoring based on the number of tricks won.