Battle system

Mega Man Star Force 2 is an action RPG much in the same vein as the first game. It is rendered in an isometric style (sprites, views, etc.) during field gameplay, but its battle system is three-dimensional, with the battles being viewed from behind Mega Man, and movement restricted to only left and right. Since enemies have a much larger playing field, battle evasion seems limited, but the player is given a choice of techniques like shielding and homing attacks to keep battles balanced. Mega Man's life is a simple "Hit point" (HP) numerical system. When he takes damage, the number lowers, and when it reaches "zero," the game is over and the player must restart from their last save point. HP can be recovered in a number of ways, both in and out of battle. The player can also use their standard Mega Buster at any time to combat with, and upgrade items for Omega-Xis can be collected throughout the game to increase the Mega Buster's rate, power, and charge speed. The Mega Buster is constantly charging to release a single powerful shot, but the player can hold the button down to fire rapidly.

Battle Cards are collected in a number of ways throughout the game, and the player must organize them into a folder to use for battles. Every time the "Custom Gauge" fills during battle, Cards are called up at random and are selected to use against the enemies. There are three different classes of Cards ranked by their power and rarity; Standard, Mega, and Giga with being able to choose a number of favorite cards to send over Nintendo Wi-fi Connection. Favorite cards were reduced in number from 6 to 4.One notable difference in folder building is the addition of Star cards and the reduction of favorite cards. Star Cards are won from Giant Viruses, bigger forms of normal viruses. They will have 1-6 stars, and increase the attack power of regular cards with the same name. While they do not count towards the 3 same-card limit, players can only have one copy of a particular star card in a folder at a time, and may only have three in their folders at once. The four elements include heat, aqua, elec, and wood. Elements are attached to certain attacks and to enemies defenses. When an element is hit with an element that it is weak to, double-damage is dealt. Heat is weak against aqua but strong against wood, aqua is weak against elec but strong against heat, elec is weak against wood but strong against aqua, and wood is weak against heat but strong against elec.

A screenshot depicting a battle sequence against EM Wave Viruses using the Wood Ninja (or "Green Shinobi") form.

Transformations

Tribe On

Three transformations exist in Star Force 2. These transformations consist of "Thunder Zerker" ("Thunder Berserk" in Japan), "Wood Ninja" ("Green Shinobi" in Japan), and "Fire Saurian" ("Fire Dinosaur" in Japan), and are activated by using a technique called "Tribe On", which can be used once Geo and Omega-Xis find a special artifact (identified in-game as an "OOPArt"). Players who get all the OOPArts go into Tribe King form. Players do this by using OOPArt cards, or Brotherband cards to transform. The transformation feature has been implemented differently in the U.S. release. The "OOPArt cards" have been removed, and as a result, transforming is only possible with brother cards or automatically with certain abilities mentioned in a later paragraph.

Using a technique called "Double Tribe," two of the three transformations can be combined to create one of six possible combinations. Double Tribe is achieved by using a brother card from a different tribe while in Tribe On mode. If a brother card from the same tribe is used, the roulette of the brother's favorites will occur instead. A final transformation - Tribe King - is also possible by activating a third tribe transformation when in a Double Tribe form; However, the Tribe King effect only lasts for three turns.

In addition to tribes, if the player is hit by an attack of the element that the current player's tribe is weak to (e.g. the player is using Wood Ninja and is hit by a fire attack), the transformation will be lost and they will return to their original state. With the Double Tribe state, players take on the element of the second transformation. Also, although there are three tribes, six Double Tribe combinations, and one triple tribe, only four transformations are possible in any version of the game (a players tribe, a players tribe x the two other tribes, and tribe king) as the players will always transform to the version they are playing first regardless of the Brother's tribe, although Wave cards allow player to transform to any form.

Rogue

A player who does not take advantage of the "Brotherband" system can take on forms based on Rogue, the rival character in this and the following game. Each tribe has a Rogue transformation. There are two ways to utilize Rogue Form. The first and normally legitimate way is to equip the six Indie Proofs on a Brotherband. Once the proofs are equipped the player gets a card which allows them to transform into the player's tribe, specific to the version. The second way to use Rogue form is to use a special "Wave Command". Rogue Form players suffer from a lack of LP, having a maximum of 400 LP (From maximized In-game brothers) instead of the absolute Maximum of 1300 LP that regular players can reach (400+150x6) thanks to Brotherbands. However Giga cards can still be used in Rogue form.

In this stage the player can not use any mega cards, but still gain skills such as a barrier that generates every turn. The Rogue Form also has no element, meaning it cannot be lost due to element advantages. Boosts from the tribe on form are also lost, instead, cards that deal 'sword' damage get a +50 attack Boost. The wave command way has the advantages over the original version as it gets certain bonuses, such as a large HP boost, Max Buster stats, Giga+1, and the Auto-ability waves First Barrier, Float Shoes, and Undershirt. Player also get to keep their Brotherbands. However, their power-ups are disabled as if players are in Rogue form, but turning off the ability gives them back. When players are in rogue form, Brotherbands with their friends will end. The main difference between the two versions is the Indie Frag Rogue Form can be activated on a player's will, using it as a strategic advantage (such as burning mega cards). The Wave command starts off a player in Rogue Tribe, meaning Mega cards aren't usable no matter what (as the form cannot be lost prematurely in battle)

New to this game are abilities, which is similar in concept to the Navi Customizer from the Battle Network series, and Link Power which is obtained by forming a Brotherband with both the four in-game brothers and with the player's real life friends, as well as an "auto-brother" which is named by the player. Abilities are equipped using Link Power, and the player can only equip as many abilities as there is link power. Link Power also has other uses in the game, such as acquiring new items. Certain amounts of Link Power are also required to take on some side-quests. In addition, if a certain ability is equipped, Mega Man can automatically start a battle in his "Tribe On" state. The player's Link Power that they give is determined to their accomplishments in the game.

Wave Command Cards

The game also makes use of 279 Wave Command Cards, actual physical cards with numbered holes on them that players can lay on the touch screen of the DS. By touching the numbers in order on certain in-game screens, the cards unlock special items, combos, bosses and cards in the game. These cards were only released in Japan but Capcom licensed Prima Publishing to print the Wave Command Card Perfect File as the "Wave Command Card Kit" in the US. This book shows all the cards and the numbers on them so US players can use all the cards. However, the instructions in the book suffer from poor translation and as a result, either make no sense at all or are simply wrong. There are three cards (specifically three of the "Mega Man Data Cards": Zerker, Ninja, and Saurian) that were misprinted with no numbers on them making them impossible to use. Additionally, while explanations of these cards are listed in the Table of Contents as being on page 9, the explanations do not appear at all. It was unknown whether or not this was intentional (i.e., in order to get the players to figure them out for themselves), or if the book had simply gone through a rushed print. Prima has recently released an update fixing the missing number issue, indicating the latter.

One special thing to note is that if the player takes all 3 Auto Tribe cards (Zerker, Ninja and Saurian), and layers them on top of each other, 6 slots will be left. If they press them in order from left to right, then top to bottom, The character will activate Auto-Tribe King, which will allow the player to use Tribe King for the next battles. All Auto-tribes will last until the game is reset or turned off.

Due to the inclusion of these Auto Forms, most specifically, Auto Tribe King, expert players are often given a hard time by unprofessional using Tribe King (as the WCCs are still active on Wifi), which has a mostly unavoidable charge attack and multiplies all card damage by 2.

The Wave command cards are actually not necessary to activate them. Simply pressing the corresponding spots in order activates them, thus removing the necessity of buying the cards if the player knows where to look.

The European version does not have Wave command cards.