Pokémon Red and Blue/Gameplay

Main menu
The main menu does not have many features at all. Upon pressing the you'll be brought to a screen with two options: NEW GAME and OPTION. NEW GAME will start a new game and get on with things. However, you might want to visit the OPTION menu to tune things to your idea of perfection. Below is a list of the settings and information about those settings.

Red and Blue
After pressing the new game button, Dr. Oak will show up and talk to you about Pokémon. After speaking, he lets you choose you and your rival's name. There are preset names for you to choose from. ASH and JACK in Red, and GARY and JOHN are pretty normal. However, the first preset name will either be RED or BLUE depending on your version. After choosing your own name, he'll present you with his grandson who has apparently been your rival ever since you were babies. You can choose his name as well, only because Oak forgot. The first choice will again be BLUE or RED (if you're playing Red your rival's name will be BLUE, if you're playing Blue it will be RED).

Moving around
Moving around is in a grid/tile style. Moving up, right, down, or left will move one space in that direction.

For more information on this topic, visit the Controls section.

Battle
The whole game is centered around Pokémon battling. Battling consists of fighting an opposing trainer with Pokémon or fighting a wild Pokémon with your Pokémon.

For more information on this topic, visit the Battle page on Bulbapedia.

Items
To access the ITEM GUI, you have to press and click on the ITEMS tab. In other generation, this is called the PACK or the BAG. None of your items are organized at all, unlike future generations. Here's a complete list of all the items in the first generation of Pokémon(note that images of items do not appear in generation one games. However, pokeball sprites do appear and they all look like this.):