The M1-A2 Thompson Submachine Gun, or simply the Thompson, is an automatic submachine gun that appears in Serious Sam 1 and the HD remakes. It is a modified replica of the original model invented by General Thompson.
"Originally invented by general Thompson, this submachine gun has survived two world wars, and with recent improvements, it is back on the track. This old-timer was modified to accept 5.56mm ammo to be compatible with other standard infantry weapons, and its universal drum container can be filled with any standard ammo pack."
Although the Thompson has perfect accuracy, the player should try to fire in bursts to avoid wasting ammo.
The Thompson is an excellent weapon against hordes of small enemies, such as Beheaded Kamikazes or other beheaded enemies. Only two bullets are necessary to kill a single target, making larger groups little threats.
It is very effective against Scythian Witch Harpies. Because of its perfect accuracy, it can be used to decimate a flock of Harpies at long range before they get too close to the player. Even at medium or close range, it can take out a flock with little to no ammo wastage. However, when in overwhelming numbers, its rate of fire and damage output rate can be a bit frustrating, so ammo reserves permitting. The XM214-A Minigun or the XL2 Lasergun might be a better choice.
Like the Schofield .45, the Thompson can be used to finish off wounded enemies at long range. The Thompson's much higher rate of fire compared to the Schofield is more sufficient, which is useful if the player is being swarmed by other enemies.
Minor Bio-mechanoids can also be cut down with the Thompson. Its perfect accuracy allows the player kill them at medium to long range before their lasers can hit the player. At close range, the Thompson is not as effective as other weapons, such as the Double Barrel Coach Gun.
This weapon is one of the ultimate anti-Marsh Hopper firearms. One bullet from this weapon can kill a Marsh Hopper, including Marsh Hoppers that appear via secrets. With burst fire, the player can destroy hordes without a problem. Sidestepping and firing at hordes of Marsh Hoppers is even more effective, as the player can reduce the risk of being hurt by their jumping attack, and also mow down dozens of them at the same time.