Differences to X-COM (OpenXcom)

OpenXcom is modelled after the original X-COM and enhances the game experience dramatically. Many features were inspired by UFO Extender and XcomUtil while others are original.

General

• None of these bugs or limits.
• Multiple ports.
• Mouse wheel support.
• Caret for text editing.
• No CPU-based speed (animations play at a constant speed regardless of the computer).
• Mouse input works like modern systems.
• Human-readable savegame format.
• Quicksave/Quickload feature.
• Autosave feature.
• No savegame limit.
• Painless customizability with modular rulesets in human-readable format.
• Full Unicode support.
• Localized in many more languages.
• Take screenshots in-game.
• Standalone "Skirmish" style custom Battlescape mission generator.
• Customizable keyboard shortcuts.
• Native support for in-game music in many different file formats (including OGG, MP3, etc.)
• A built-in and extendable selection of optional display filters.

Geoscape

• Since there's no 80 item limit, items in crafts count towards your Base Stores to prevent exploiting infinite storage. This also lets you freely move items between bases and crafts without storage issues.
• Each radar facility contributes to the detection check, so having multiple Small Radar Systems and/or Large Radar Systems does improve your chances. The Hyperwave Decoder still makes all other facilities obsolete though since it has a 100% detection chance.
• The aircraft phase order when returning to base is: Repairing, Rearming, Refueling.
• Purchase/Recruit screens have a column for current storage.
• Aircraft weapons may be unequipped.
• Can cancel out of selecting armor for soldiers.
• Selling aircraft automatically unequips all their contents.
• No gap in Australasia zone.
• Soldiers can be reordered in aircraft.
• Soldier equip screen accessible from aircraft equip screen.
• Soldier equipment is saved for each soldier and restored as possible before mission.
• Aircraft can be renamed.
• Right-mouse-button clicking on arrow buttons that increase will set value to maximum (research, manufacture, buy/sell, equip...).
• Right-mouse-button clicking on arrow buttons that decrease will set value to zero (research, manufacture, buy/sell, equip...).
• Right-mouse-button clicking on base facility graphic will open corresponding screen.
• Potential radar coverage will be displayed when placing a new base.
• Aircraft will use proper great circle calculations when travelling so they'll always take the shortest path along the globe.
• Aircraft have better fuel calculation so they will always travel the maximum their fuel supply will allow.
• Night/Day line is dithered slightly.
• UFOPaedia articles regarding Aircraft weapons have flavour text (unused strings existed in the original were implemented).
• Optional display of current funds in Date/Time field (toggled in "advanced options" from the main menu).
• Mouse Wheel will zoom in and out.
• Aircraft weapons can be temporarily disabled (by clicking on the weapon item in the dogfight screen).
• Globe can show radar coverage and flight paths.
• Manufactured items can be automatically sold directly, bypassing the stores.

Battlescape

• Objects, fire and smoke keeps animating while walking or scrolling the screen.
• Pathfinding is a different algorithm: it will always find a solution, if there is one, no matter how difficult.
• AI of aliens is more cunning - Impossible to 100% exactly mimic original AI.
• Waypoint-based projectiles have no upward limit on the number of waypoints they may use.
• The inventories of mind controlled, non-terrorist aliens may be accessed.
• Can use special abilities of mind-controlled aliens.
• The limit on units has been removed, allowing 23 or more soldiers to assault alien bases.
• Unit spawning function has been improved - no more large units stuck in walls.
• Units holding two single-handed weapons will have the fact represented on their sprite.
• Soldier sprites will have their hair and skin recolored to represent their race.
• Can cancel out enemy's mind-control with your own.
• "Not enough equipment" screen shows items missing.
• At the end of the mission, ammo from clips is totalled, so you only lose enough clips to match the total ammo used (as opposed to losing any used clip).
• Soldier equipment loadouts are automatically saved.
• Soldier rank and stats accessible from inventory.
• Can load game from Battlescape.
• Right-click opens doors.
• Right-click will cancel a unit's movement, and will cause projectiles to "skip" their flight paths, instantly hitting their target.
• Possibility to use "force fire" when no line of sight is available. (CTRL + Left Mouse Button for firing)
• Mouse Wheel changes levels.
• Keyboard scrolling (arrow keys by default, can be re-assigned)
• "next soldier" / "previous soldier" keyboard shortcuts ("TAB" for next, "SHIFT" for previous)
• lots of keyboard shortcuts (for example TU reservation, kneeling, center on visible aliens... can be viewed and re-defined in advanced options)

Optional features

While the above differences are hardcoded, there are also various new "non-vanilla" features you can choose to enable, such as gameplay features and keyboard shortcuts. See the Customizing section for more information.