Espresso is different than coffee brewed in the traditional way. Rather than hot water being poured over coarsely ground coffee beans, the nearly boiling water is forced at a high pressure through finely ground coffee beans. Traditionally a barista would a handle to force the water, resulting in a “shot”. These days, you can get espresso machines to do that for you. A layer of form, or “crema” will form on top of the drink.
An espresso shot is highly concentrated coffee. Some drink it straight up, but typically you’ll want to mix it with water to make a Cafe Americano, with milk to make a Cafe Latte, or with milk and chocolate syrup to make a Cafe Mocha.
It's pretty clear that the inspiration for Animal Crossing's Espresso Maker is the Breville Barista Express (as well as other copycat products you'll see on Amazon). You can see the round container on the top where you put your beans, the scoop where the ground coffee beans go into, the milk frother, and the buttons and gauges to monitor water pressure. We have one at home, and even though it's a pretty hefty price, it pays for itself in saved trips to Starbucks (Also, you can usually get good deals around Black Friday and the holidays).