# What the Earthsiege expansion adds

The Mission Disk adds Battleset 2 and extends the existing simulator to support new enemies, arrivals and weapons. The main additions are:

- **Three campaigns and career transfer.** There are 24 campaign mission files, arranged in three groups of eight, plus 13 standalone missions. You can switch between the original battleset and Battleset 2. The manual describes copying an existing career into the expansion at any point, optionally bringing its HERCs and salvage. The original career remains available; transfer works only towards Battleset 2. A fresh expansion career starts with medium/heavy HERCs and an experienced squad.

- **New machines and enemy arrivals.** The player gains the Apocalypse; the Cybrids gain Diablo and Headhunter. Heavily armed landing craft have their own behavior and weapon records. The manual gives them a capacity of ten Cybrid HERCs. Atmospheric entry pods also have an implementation: the simulator creates ballistic `METEOR` objects associated with waiting groups. These resources support scripted reinforcement arrivals.

- **Weapons with additional behavior.** PBW2 and ELF2 offer greater range and power according to the manual. EMP2 adds a paired-shot mechanism: the first discharge retains its charge and uses a shorter refire delay, and the second consumes the charge. The plasma launcher introduces a projectile with limited homing and an area impact. The paired discharge is confirmed by original-code probes; the plasma guidance and impact branches have been traced in the executable.

- **Scenery and presentation.** `WASTE` and `RUINS` add terrain families with explicit texture-bank bindings. There are replacement building and weapon meshes, cockpit artwork, palettes and world settings. The CD also contains expansion speech, new introduction/victory movies and 13 additional music resources, none byte-identical to a base-game song.

- **Changes to ordinary projectiles.** Bullet lifetime now follows simulation time instead of counting updates, changing expiry at different frame rates. Projectile records also gain launch-spread and power-falloff fields. The falloff path has a preference/development-state guard, so its presence alone does not establish that it operates in every normal game configuration.

- **Bundled control and usability improvements.** These include choosing initial career difficulty, holding Alt for faster keyboard turret movement, reversing rudder controls, improved Thrustmaster throttle support and additional CH device support. The manual says some were already available through the earlier patch. The README also records corrected displayed weapon ranges, with actual ranges unchanged, and corrected movie playback speed without a sound card.

There are later fixes within the expansion family too. Our floppy executable corrects scanner placement; the April patch additionally improves retired-effect cleanup and allows the next queued radio message to start correctly. Those are revision differences rather than additions common to every expansion copy.

The executable also contains unfinished 320x400 display layouts. Our DOSBox captures show overlapping views or misplaced instruments, so these do not amount to a supported higher-resolution mode.

We have not completed a rule-by-rule comparison of base and expansion damage, salvage and AI. The additions above do not establish that all other gameplay is identical.

Sources: [media and content audit](../../docs/INSTALL_MEDIA.md), [executable comparison](../../docs/SIMULATOR_VERSIONS.md), [expansion manual OCR](../../literature/expansion_1995_03/manual-ocr.txt) and [original README](../../literature/expansion_1995_03/README.TXT).