After the player passes some Star Posts in Red Gate Bridge, the Metal Sonic replica will appear on the bridge and proceed to run away from the player. Throughout the battle, a wall of energy cubes will chase the player, causing damage if they are not moving fast enough or stall in place for too long. Red Star Rings will also appear for the player to collect early into the fight.
Metal Sonic's main attack is to create harmful pillars of energy using electrified versions of Infinite's energy cubes. To damage him, the player must boost to get close enough to use a Homing Attack on him. When Metal Sonic's health drops below half, he will change his attack pattern and begin using the V. Maximum Overdrive Attack, which must be avoided either by jumping over it using Quick Step. The player can also hit him with the Drill Wispon, Cube Wispon, or the Super Sonic Boost when he charges to deal damage. He will also protect himself by gathering Moto Bugs and Egg Pawns when the player gets close, which can be knocked away with consecutive Homing Attacks, or the Boost. Once the Moto Bugs and Egg Pawns have been cleared out, follow it up by Homing Attacking Metal Sonic.
The player must not take too long to defeat Metal Sonic. If they take too long, they will eventually come to a dead end where Metal Sonic escapes and leaves the player to be caught by the cube wave, thus forcing the player to restart the fight.
When enough damage has been dealt to Metal Sonic, the player will be prompted to use a Double Boost to rush down Metal Sonic, landing the finishing blow.
Metal Sonic is the only boss in Sonic Forces that is fought in a regular stage.
Due to this, he is the only boss that can be fought with Super Sonic.
Metal Sonic is also the only boss battle in Sonic Forces not to have a trophy attached to it.
Metal Sonic is the only boss that contains Red Star Rings, Silver Moon Rings, and Number Rings.
The giant Metal Sonic replica could be a reference to his intended boss fight in Sonic X-treme.