The Thompson is an automatic weapon that uses one bullet every time the gun is fired. The Thompson has perfect accuracy, no matter how many bullets are fired. Despite having a visible magazine, the Thompson does not have to be reloaded in most of its appearances, though it does need to be reloaded in Serious Sam's Bogus Detour and Serious Sam 4.
In Serious Sam 1, the Thompson is a replica of the original model invented by General Thompson, which has been modified to accept 5.56×45mm NATO rounds.
In Serious Sam 4, if the player purchased the Digital Deluxe edition of the game, they can select the Thompson as a skin to replace the M29 Infantry Assault Rifle. This change is purely cosmetic and is identical in terms of performance with the assault rifle.
It is very effective against Scythian Witch Harpies. Because of its 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 XL2 Lasergun or the XM214-A Minigun might be a better choice.
It is a good weapon to use against juvenile Arachnoids, but it is not recommended to be used against adults due to their higher health and the possibility of wasting ammo.
The ammo for it is fairly common, allowing the player to use it for extended periods of time.
Minor Bio-mechanoids can also be cut down with the Thompson. Its accuracy allows the player to eliminate 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 in 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.
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.
The Thompson is very useful for taking out groups of medium-strength or weak enemies, such as Methug Commanders or Kamikazes. It has a fast enough rate of fire and does enough damage per bullet that it can wipe out a group fast enough.
The Thompson is an excellent weapon overall. It does a good amount of damage and has a consistent and good rate of fire. This makes it a great weapon to use with nearly any gunstack combination as either the main focus or as a supplement weapon for more powerful ones. However, the Thompson does too little damage against strong enemies, such as the Caterfighter.
The Thompson is useful for doing extra damage while using stronger weapons, such as the LM32 Rocket Launcher.
When upgraded with upgrades such as the Death Adder or Death Bringer, this makes the Thompson much more effective, especially when stacked with other upgraded weapons.
The Thompson can receive several upgrades in Serious Sam: Double D: XXL. These upgrades can be purchased from The Trader using Cerebral Controllers. The last upgrade, Turret Tosser, is unlocked after completing the game.
Fires large caliber shots that are able to bounce off the ground and can strike enemies.
Death Adder ($150)
After hitting an enemy each bullet travels through the creature, exiting and splitting into two additional shots.
Death Bringer ($300)
Seeking bullets with a high rate of fire. Can still hit the ground.
Turret Tosser ($450)
Creates turrets that will attack enemies for the player. They use bullets as ammunition. The longer the fire key is held down, the more ammo the turret has.