Action Master is the fourth Challenge Act of Planet Wisp Act 2 in the console/PC version of Sonic Generations. It is unlocked after clearing every Stage in the modern era and is playable only as Modern Sonic.
The Challenge Act is modified to include a large variety of gimmicks, obstacles, and moves. This include Ring trails for the Light Speed Dash, collapsing platforms, Dash Rings, narrow Wall Jump Blocks, fire and electrical-based traps, Spinning Platforms, Four-way Cannons, Horizontal Bars, Badniks, and Balloons.
The objective of this Challenge Act is to reach the Goal Ring at the end of the course. However, the course has been modified with several elements and gimmicks that require pinpoint accuracy and well-timed actions for it to be completed properly.
As the Challenge Act begins, the player has to ride a Ring trail with the Light Speed Dash to a 2.5D perspective area. Here, the player must Stomp and Wall Jump in between small Wall Jump Blocks, and use Switches to deactivate traps to get through a series of platforms. After that, the player enters another 2.5D area with both platforms, Spinning Platforms and small Wall Jump Blocks which must be scaled to reach some Ring trails. Using the Light Speed Dash at them will take the player to a Grind Rail section similar to the one in the original stage, but without the Trap Springs. After making it through it can clearing a Zip Line/Ring trail section, the player arrives in another 2.5D area. Here, the player has to use Horizontal Bars and Wall Jump Blocks to scale vertical spaces. Making the jumping harder, the player has to at the same time avoid electrical fields and press Switches to shut down traps. Upon completing this section, the player reaches a Ring trail that leads to the Goal Ring.