You asked if the pitcher is trying to outgun the batter.....the answer is: only sometimes!
Some pitchers throw fastballs for most of their pitches while other pitchers rarely throw fastballs . But it should be noted that a fastball isn't always "fast". What I mean by that is that the speed of a pitch, and whether or not it's a fastball, is based on relative comparisons. These relative comparisons aren't made from pitcher-to-pitcher; rather, the comparisons of pitch speeds are important within the repertoire of pitches that a particular pitcher uses during the game.
So, a pitcher like Aroldis Chapman has a "fast fastball" (100-104 mph), while a pitcher like Jamie Moyer (recently retired) had a "very slow" fastball (80 mph). Flamethrowers like Chapman are indeed trying to outgun a batter. There are quite a few bazooka-arm pitchers in MLB, and they do the same thing as Chapman. But there are a lot of pitchers who are very successful because they fool the batter into thinking one type of pitch is on its way to the plate when it is actually another type of pitch. Or, these pitchers can make the ball "break", which means they can do what the guys do in cricket and put such a spin on the ball that it will curve or slide or jump or drop or any number of other things that really seem to be impossible.
Good pitchers beat the batters because they win the mind game that goes on with every pitch. One of my favorite pitchers was Greg Maddux (now retired). All the players said the same thing about him: that he always seemed to know what you (the batter ) were expecting, and then he would pitch the opposite of what you were expecting.
Here is a short video to show you some of the types of pitches. When you see the pitches go into the dirt, that is being done on purpose (not because the pitcher has lost control). The batters are swinging on those pitches because they are seeing a delivery by the pitcher that makes them think a higher-up pitch is on the way. By the time they start swinging the bat the ball is in the dirt and there isn't anything that can be done with it.
You'll also see a pitch called a change up. This is a pitch where the pitcher does everything the same as with his fastball delivery, but because of the grip on the ball the velocity is 5-8 mph less than what the batter thinks is coming his way. A good change up pitcher will almost always make even the best batter look like a not-so-good batter.
If you're still interested, I'm sure all of us here can keep feeding information to you about our beloved version of 'Rounders'.
Just ask away....