The gameplay of Mega Man Battle Network 5 is largely similar to that of its predecessors. The player explores the real world through Lan and the Net through MegaMan.EXE. When Lan plugs his PET, a handheld computer, into a computer with an interface jack, he can upload MegaMan.EXE to the cyber network, allowing him to explore and fight viruses as random encounters.[11][12]
When MegaMan.EXE encounters viruses, the screen shifts to a battle screen set on a six by three square grid. On the left half of the grid is MegaMan.EXE, and on the other half are his opponents. MegaMan.EXE has a relatively weak arm cannon, the Mega Buster, but his main weapon is Lan's library of battle chips, one-use-per-battle special attacks which grant various abilities, including simple attacks, attack enhancements, defensive effects, terrain transmogrification, or assistance from other NetNavis. Before battle, the player can construct a folder consisted of thirty battle chips, and each turn of a battle (measured by a timer bar at the top of the screen), the player is presented with a random selection of these chips. The player can send MegaMan.EXE up to five battle chips, after which the battle takes place in real time, with MegaMan.EXE, controlled by the player, attacking with his Mega Buster, dodging attacks, or activating battle chips from his queue.[11][12]
MegaMan.EXE joins a team led by either Lan's and MegaMan.EXE's rivals Chaud and ProtoMan.EXE or new characters Baryl and Colonel.EXE, and the members of this team assist MegaMan in various ways. MegaMan.EXE can take on the attributes of one of his teammates with a Soul Unison.[11] The team plays its largest role in Liberation Missions, wherein MegaMan.EXE and the rest of his team enter a part of the Nebula-controlled Internet to free the area via a time-limited battle with a group of viruses.[11][12][13] The Dark Chip system from the previous game was also reworked, with them now having to be obtained; it is also possible to use them to activate a "Chaos Unison", which resembles a normal Soul Unison with the main difference being that the Mega Buster is replaced with the effects of the Dark Chip he used for the Chaos Unison. While using this effect doesn't cause HP loss, it has to be done with careful timing, as charging with poor timing will end the Chaos Unison and cause an invincible, evil version of MegaMan.EXE to join the viruses and attack him for a short period of time using random battle chips.[11][13]
Much like previous games in the series, Game Boy Advance copies of Mega Man Battle Network 5 can connect using the Game Boy Advance link cable to battle head-to-head or to trade battle chips.[11] Battle Network 5 also includes content referencing the Boktai series by Konami,[14] such as a crossover battle feature unlocked by combining both Battle Network 5 and Boktai 2: Solar Boy Django.
