Revving a chainsaw in public will cause pedestrians to panic (if some are armed with a weapon, they may even retaliate against the player) or enemy gang members to attack the player, and, if a police officer is nearby the player will gain a one-star wanted level, regardless of whether the player harms anyone in the process, with the exception of GTA San Andreas.
The chainsaw can easily remove parts such as hoods, bumpers, and even doors from vehicles. However, its blows glance off vehicles' main chassis, thus causing only superficial damage. The chainsaw's ability to easily remove vehicle parts is a huge benefit in Paramedic missions, reducing the time the patients have to get in the ambulance. Strangely, chainsaws cannot saw off locked car doors, nor can they saw off doors of helicopters.
In GTA Vice City drops of blood can be seen spattered at the screen when the player successfully attacks a target (only if "Trails" are turned on in the display settings; the same goes for water droplets on the screen).
In GTA San Andreas the player cannot jump up or over obstacles with the chainsaw equipped. As such, it is unsuitable for attacking fleeing targets.
In GTA Vice City Stories, pressing "square" while holding the chainsaw will make Victor Vance swing it; the animation resembles that of the Katana, and the chainsaw makes the same sound upon striking an opponent.
In GTA Chinatown Wars, you can hijack cars in front of police by using the chainsaw on the car. When the passengers walk out, take the car without any worry of alerting the police, but be careful of accidentally killing the escaping passengers.