Certain missions, however, will dictate certain ships and weapons to be used. Weapons can be classified into primary weapons and secondary weapons. Primary weapons are kinetic and energy weapons, while missiles and torpedoes are classified as secondary weapons. Each weapon has its own specifications such as its rate of fire. They also inflict different damages on hulls (body of the ships) or shields (the protective energy fields surrounding the ships), or possess special effects such as shutting down specific electronic systems or propulsion. The player flies around in a fighter with a first-person, in-cockpit view with a fully customizable fixed head-up display (HUD) as the visual interface. The HUD displays video communications and relevant data on the ship's status and performance, weapons, objectives, and targets. It can also warn players from which direction missiles are locking onto them from, thus becoming an aide for launching countermeasures or taking evasive maneuvers. Players have to maneuver into position and shoot through both shields and hull to destroy enemy ships. While hull damage is unrecoverable, shields recharge over time. With the game supporting force feedback technology, joystick players will find their controllers vibrating or putting up resistance when they engage the afterburners or collide with objects. Similarly, certain events, such as engaging afterburners and firing powerful weapons, will shake the screen as a form of visual feedback. FreeSpace 2 has many helpful features available. The player can target enemies attacking a protected objective or match speeds with them. Power can be shunted between shields, engines, and weapons, thereby allowing faster recharge of shields, afterburners, and weapons at the expense of other subsystems. These features can be ignored without any detrimental effects on gameplay. The mission parameters are not rigidly fixed, as there is an allowance for the failures of some primary objectives. When the mission is concluded, a post-mission briefing will be conducted to discuss the mission, and the performance of the player, before the next mission can be taken on. FreeSpace 2 allows multiplayer games to be played across a local area network (LAN) or over the Internet via the free services provided by Parallax Online (PXO). The player can communicate with the other network players vocally through FreeSpace 2s own voice chat capability. LAN play allows the players to play the standard player versus player modes such as deathmatch, or cooperate to complete multiplayer missions. They can even join in games