The Rifleman appears as a fair-skinned man with a blue uniform, simple boots, and a grayish-green helmet with a blue cloth band around it. He carries a rifle and has a red ace of spades tucked into his helmet band.
The Rifleman is effective when deployed in large numbers.
The Rifleman is effective when used with Heavies acting as meat shields.
Another great strategy is Rifle-Medic. Riflemen have moderate health, so Medics will be able to heal up most of the damage that the Riflemen take from splash damage defenses. Medics' healing does have a splash effect, so they can heal Riflemen faster than any other unit (though high-level defenses can eventually overpower the healing).
The Rifleman is great to use against Cannons and Boom Cannons as these defenses are single-shot defenses, making them easily overwhelmed by Riflemen hordes.
Use a Barrage on large groups of Mines to prevent them from killing your Riflemen quickly.
A group of Riflemen's worst enemy is the Rocket Launcher, so place it well behind other defenses.
The Mortar is effective in taking out large numbers of Riflemen, but it fires very slowly. Having a Machine Gun in front of a Mortar will cause the Riflemen to target the Machine Gun (in the absence of a Flare), giving the Mortar more time to fire at the Riflemen.
Place the Mortar behind various buildings so that it is difficult for the Riflemen to reach the Mortar without having any casualties, the same goes for any other slow-firing defense.
Cannons and Boom Cannons can easily one-shot kill Riflemen but can be swarmed by large groups of Riflemen so be sure protect them with Sniper Towers, Machine Guns, Flamethrowers, Rocket Launchers or Shock Launchers.
Place your Mines well. Groups of them can kill Riflemen quickly.
There are no visual changes between levels, but each upgrade increases the Rifleman's hitpoints (by 7%), DPS (by 8%), and training cost.
They appear as the snipers in Sniper Towers. However, their rate of fire is different.
During the tutorial, the training time of 5 Riflemen is reduced to 5 seconds, and costs 0 Diamonds to complete.