text: In addition to the main gameplay missions, the player can attempt to find special large bolts that are typically hidden or difficult to get to that can be used to upgrade or buy powerful weapons. There are also Skill Points spread throughout the game, which require the player to complete a specific task guided only by the name of the Skill Point. Skill Points are used to unlock extra features such as concept artwork or additional outfits for Ratchet. Each game (excluding Quest for Booty, All 4 One, and Full Frontal Assault) also presents a "Challenge Mode", available after the player has completed the main story; in this mode, the player replays the game, facing more difficult enemies in exchange for a higher bolt payout or more powerful weapon upgrades.
  Reception
  Games in the Ratchet & Clank series have been met with mixed to universally acclaimed reviews, with review aggregator scores ranging from 54/100 to 91/100 on Metacritic, and 57% to 92% on GameRankings. The first three games, Ratchet & Clank, Going Commando, and Up Your Arsenal in particular have all been met with critical acclaim. None of the core games in the series (Ratchet & Clank to Deadlocked, the Future series, the PS4 game, and Rift Apart) have been rated below 76/100 on Metacritic. 2016's Ratchet & Clank became the fastest-selling game of the franchise.
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