Combo

Combos, also known as Hits, are a recurring game mechanic that appears in the Sonic the Hedgehog series. It is a term for a set of sequential actions performed for the benefit of the player.

Description
Combos can be defined as a designated a set of actions performed in sequence that yield a significant benefit or advantage to the player. This usually include providing the player with extra points the larger their combo becomes, alongside other rewards exclusive to each game. However, Combos have strict timing limitations, meaning they will broken if the player takes too long to execute a combo-building action. Similarly, taking damage during a combo will break it as well.

Sonic Unleashed
In Sonic Unleashed, combos can only be performed by Sonic the Werehog during the nighttime Action Stages/Stages. In this game, they are activated and maintained through attacking enemies. When building a combo, a counter for the current number of hit accumulated named the "Combo Counter" appear on the left side of the screen.

In the Xbox 360/PlayStation 3 of the game, combos are more free-flowing and without limitations. When completing a nighttime Act, the player will receive a point bonus based on their combos on the result screen. Additionally, the player will received Dark Gaia Force and increasing bonus points when reaching certain combos:

Sonic and the Black Knight
In Sonic and the Black Knight, combos, referred to as hits, are activated and maintained through killing Knights of the Underworld.

Alongside giving the player extra points the higher the combo goes, the player will also start to be rewarded with rings if their combo reaching 15 hits or higher with each following hit they land.

Sonic Runners
In Sonic Runners, players can activate and maintain a combo through collecting crystals and collecting rings. As the player's combo rises, they will be granted a bonus score for each following combo they manage to maintain the combo.
 * With a 1-99 combo, the player is given a 1 point bonus.
 * With a 100-149 combo, the player is given a 5 point bonus.
 * With a 150-199 combo, the plater is given a 10 point bonus.
 * With a 200-249 combo, the player is given a 15 point bonus.
 * With a 250-299 combo, the player is given a 20 point bonus.
 * With a 300-399 combo, the player is given a 25 point bonus,
 * With a 400- 999 combo, the player is given a 30 point bonus.
 * With a 1000+ combo, the player is given a 50 point bonus.

The combo bonus item will prevent the player from losing their combo regardless of how long they go without grabbing a ring or crystal or if they get hurt by an enemy or obstacle. In addition, it will double the bonus given to the player; if they player is receieving a 10 point bonus, it will be made into a 20 point bonus. The combo bonus, at level 10, lasts for 10 seconds.

The following buddies affect the player's combo in some shape or form.