Rebelstar Games ZX Spectrum


Rebelstar Games ZX Spectrum



Developed by Julian Gollop and released in 1984-88 for the ZX Spectrum microcomputer, Rebelstar is a seminal tactics wargame franchise famous for formalizing features of the tactics genre, thereby paving the way for Laser Squad, X-COM UFO Defense and Jagged Alliance.

The three Rebelstar games are:

  • Rebelstar Raiders (1984)
  • Rebelstar (I: ISAAC) (1986)
  • Rebelstar II: Alien Encounter (1988)

In Rebelstar games, players control a squad of raiders in battle against either another human player or AI-controlled forces such as ISAAC operatives or the Aliens (Alien, 1979).

The object of Rebelstar games is simple: one player raids the stronghold, the other player or AI defends it. Rebelstar Raiders has three scenarios fleshed out by a story: Moonbase, Starlingale and The Final Assault.

Whereas Rebelstar and Rebelstar II have one scenario each: ISAAC and Alien Encounter. 

Rebelstar Combat System


A Giger-esque Alien Queen guarding the eggs in her lair.

Rebelstar employs a simple but robust and precise turn-based combat system, which means that actions by both players and AI are taken in discrete turns (as in Chess and traditional wargames). The battle (movement, attacks) continues in discrete turns until one of the players or AIs have emerged victorious; that is, the enemy forces have been vanquished and the mission objective has been satisfied.

Upon making a move, the opponent makes their move. The opponent's moves are observable; there is no hidden movement and no fog of war [1]. During the opposing player or AI turn, players may not intervene in any way, shape or form until their next turn [2], at which point viewport control is returned to them. On their next turn, players take their next set of actions and adjust their tactics based on opponent actions in the preceding turn.

Rebelstar gameplay places great emphasis on avenue of approach and the positioning of combat units: the difference between good and bad positioning is the difference between life and death. Avenue of approach is limited by terrain squares such as rivers, walls and other obstructions.

There are three control modes in Rebelstar:

  • Cursor Mode
  • Movement Mode
  • Ranged Combat Mode

Movement and ranged combat (e.g., firing a gun) are based on Action Points, aka "energy." The more APs combat units have, the more they can do during their turn; that is, the more tiles they can move across and the more attacks they can execute per turn.

Action Points were later employed by:


Pretty good games, eh?

Cursor Mode Rebelstar


Via keyboard, Rebelstar combat units are moved about in eight directions on a top-down tile-based field of play. Combat units can be moved diagonally, not just horizontally or vertically.

The cursor is a blinking square that is freely moved around the playing field with Q-W-E, A-D and Z-X-C keys. The screen scrolls in tile by tile increments when the cursor or combat unit attempts to move beyond the edge of the screen, aka edge-screen scrolling. [3]

When the cursor is positioned over a combat unit, the combat unit can be selected, commands can be given to the combat unit and information (stats) about the combat unit can be called up.

  • I: Information about a combat unit.
  • P: Information about the combat unit's weapon.
  • S: Select combat unit to enter movement mode.
  • V: Display combat unit's victory points, the required victory points to win, and the number of game turns remaining.
  • 0: End Turn.
  • N: Switch to next combat unit in the squad.
  • J: Center viewport on cursor.

Movement Mode Rebelstar


  • I: Information about a combat unit.
  • P: Information about the combat unit's weapon.
  • V: Display combat unit's victory points, the required victory points to win, and the number of game turns remaining.
  • F: Enter ranged combat mode (firing mode).
  • K: End movement and return to cursor mode.

Ranged Combat Mode Rebelstar


  • S: Select target.
  • K: Return to movement mode.
  • O: Equip weapons at the start of play (up to 4 items).
  • M: Drop equipped object.
  • L: Load firearm.

Rebelstar (I) introduced three additional firing modes that would appear in X-COM UFO Defense:

  • Aimed Shot (Active)
  • Snap Shot (Active)
  • Opportunity fire or "interrupts" (Passive aka auto-taken on enemy turn)

Rebelstar Combat Unit Stats


  • Movement Points (Action Points): How many tiles a unit can move across as well as how many times a unit can fire its weapon per turn (depends on weapon's MP cost).
  • Endurance: How many wounds a combat unit can sustain before it is killed.
  • Weapon Skill: Accuracy in hitting the mark. Gives percentage to-hit chance (not actual inflicted damage chance).
  • Armor Rating: Decreases wounds incurred.
  • Victory Points: Increased by killing enemies. Required for victory condition in scenarios.
  • Morale: Penalizes APs when combat unit morale-fails.
  • Stamina (Energy): Governs APs. Partially replenishes on a turn-by-turn basis depending on combat unit status.
  • Constitution: Hit points. When HPs reach 0 the combat unit is vanquished. APs are penalized at Con 50%.

Weapon stats (P-key) include to-hit chance (accuracy), movement (firing) cost, close-combat damage, ranged combat damage and no. of rounds chambered.

[2] The only exception is in Rebelstar II, which introduced opportunity fire or "interrupts". But that is automated.
[3] Bear in mind that we are talking about a game that runs on 8 bit Z80A microprocessors clocked at 3.5 MHz. With 48 KB RAM. Tile-based edge-screen scrolling was standard in the 80s and 90s.

As regards home microcomputers, per-pixel hardware scrolling at 50 FPS was the exclusive province of the Amiga 16 bit microcomputer from 1985 to 1988. At that time, it was seen nowhere else outside of coin-op chipsets and graphics workstations at Silicon Valley.


No comments:

Post a Comment

Note: only a member of this blog may post a comment.