Mega Man Battle Network is an action role-playing game developed by Capcom for the Game Boy Advance. It marks the debut of the Mega Man Battle Network series and eventually spanned another six games.
The player alternately controls two main characters, Lan Hikari and Megaman.EXE, also the name of the game itself). Lan is a human while Mega Man, is a computer program called a NetNavi also known as a (Network Navigator) designed specifically to link the user's (Lan's) interaction with the Net and other computerized devices. In the series, the Internet and the inner workings of computers are displayed as a material world which computer programs of all varieties, as personified in a humanoid form, can interact with via the NetNavi.
The game typically proceeds as follows: the player follows Lan and his daily activities, such as going to school or visiting his father at work. Eventually, a crisis breaks out, and Lan is forced to "Jack" Mega Man into Cyberworld in order to put down the threat. The player must navigate the labyrinthine area and solve a puzzle, all the while fending off randomly-occuring viruses; when Mega Man reaches the end of the Cyberworld (typically after 4 areas), he must fight the enemy NetNavi to clear the level and continue with the story.
In addition, there is a primary Internet which the player can explore. The Internet in this game can be somewhat overwhelming, given that there is no indication of where you are in addition to all areas looking the same, as well as the presence of randomly triggered encounters, but future games in the series would vastly improve the Internet design (perhaps because they rely on it much more).
One of the most famous (or infamous, depending on point-of-view) features about Mega Man Battle Network is its battle style; instead of being a platformer like a majority of the Mega Man meta-series, Battle Network is a card-based Action RPG. This game establishes the battle system that would be improved upon in Battle Network 2 and further refined in subsequent games.
The battlefield is a 3x6 grid, split into red panels (which MegaMan.EXE can walk on) and blue panels (which the enemy can walk on). There are two types of battles: Virus Busting (random encounters in which 1-3 viruses occupy the enemy side) and NetBattling (the player goes one-on-one against an enemy Navi).
The trademark Mega Man weapon, this arm cannon fires fast, extremely weak shots. By holding the button down, you can eventually charge up a shot, which can be released for extra damage.
The primary method of attack in the Battle Network series, these are single-use cards with varied effects.
Custom Screen and Custom Gauge
The Custom Screen opens at the start of each battle. In it, you can choose up to five BattleChips to send to MegaMan for this turn. However, you are restricted to choosing either chips of the same name (such as Cannon A and Cannon C) or chips with the same "chip code" (such as Cannon A and Minibomb A). During each turn, the Custom Gauge at the top of the screen slowly fills up. When it is full, pressing the L or R button will reopen the Custom Screen.
By pressing the ADD button, MegaMan goes a turn without any chips. When the Custom Gauge is reopened, the player will have 10 chips to choose from for the next turn. By repeating the process, the player will have 15 chips to choose from for the next turn.
A special, high-powered BattleChip created by selecting three or four chips in correct order at the Custom Screen.
The player's deck. The folder consists of exactly 30 chips; in this game, only ten copies of a single chip are allowed. Additionally, only five NaviChips (chips based on Navis, such as Roll, GutsMan, and FireMan) are permitted.
Exclusive to this game, the player can buy Fire Armor, Aqua Armor, or Wood Armor; this armor will halve all damage dealt to MegaMan EXCEPT attacks that the armor's element are weak to (Aqua beats Fire, Elec beats Aqua, Wood beats Elec, Fire beats Wood)
Power-ups are used to increase the stats of the MegaBuster. There are three categories: Power, Rapid (Speed in later games), and Charge.