To actuate a linear switch, you must press it all the way to the bottom, similar to a membrane key. The original Cherry MX Black is a linear switch, as is the Cherry MX Red.
The most popular tactile switch (without an added click) is the Cherry MX Brown. Linear switches in comparison have no notable resistance or bump until the key bottoms out. Whereas a linear switch with no feedback can cause you to get a little tired while keeping it down for long since you don't know if the key is still engaged, so you tend you push the key all the way to the bottom and keep it there the entire time. This is because you can feel the bump so you know that its still actuated. This bit of tactile resitance or feedback is particularly useful in games that require you to keep a key pressed down for a long time, like when walking or running in a game. This bump does not make an obvious noise, but it can be felt by your finger tip when the key is pushed down. There's a bump in the switch and to get past the bump, you need to apply enough pressure. Razer likes to hype theirs up for "gaming" because they use light to register keystrokes.Tactile switches have some type of physical resistance at the point at which the switch is actuated. There're also optical switches (Razer Optical Switches, Gateron Optical Switches, Flaretech, Etc.). Razer likes to hype theirs up for "gaming" because they use light to register keystrokes. (Big deal? ¯\_(ツ)_/¯) For instance, I have both the Kailh Speed Gold (Clicky) and Kailh BOX Jades (Clicky), but I find the BOX Jades (50g Actuation Force, 60g Bottom Out Force, 1.8mm Pre-Travel Distance) provide a more consistent and more satisfying typing experience than the Speed Golds.
To compare two extremes of linear switches: I use Kailh BOX Ancient Grays (linears) with a ≈95g actuation force as my daily driver. However, the Cherry MX Speed Silver (also linears) have an actuation force of ≈45g. If we're talking about "force," I'd say it depends more on the switch's springs, instead of whether it's designed to be clicky/tactile/linear. I’ve heard linear is best because it required the least amount of force.