Thrust

Origins
Gravitar was not a big hit when it debuted in the arcades in the early 1980s, as it was definitely not for people who couldn't handle thrusting around very well while performing various other duties around a very tight-knit atmosphere, like with Asteroids.

Conditions were much more closed off with Gravitar though, unlike with the free range of Asteroids, since the player had to fly around caverns and various landscapes in a series of planets to destroy bunkers, beam up fuel cells, and contend with gravity as well. One critic dubbed it as to being "the worst game ever made" due to its difficulty level.

So, one might question the business tactic of a video game company that would take the inspiration of Gravitar, yet arguably make it even tougher by having the player deal with flying off planets with a pod attached, causing their ship to, at times, swing like a pendulum if they weren't careful. However, somehow Thrust actually worked, as the game was ported around to many platforms.

Story
The Intergalactic Empire has a diabolical plan, as they have captured many battle-grade starships to launch an offensive against their resistors. The one thing they need in order to launch their plan are Klystron Pods so their starships can be powered.

It is the player's mission to infiltrate the Intergalactic Empire's planets and steal their pods to prevent their plans from taking effect.

Gameplay
The player must penetrate planets to make it to the pod bases. They then must engage their tractor beam to attach the pods to their ship, then navigate off the planet with the pod still attached to complete their mission.

The player has to contend with many factors during their mission; one of which is the consumption of fuel, which is drained whenever thrust is applied and their shield/tractor beam is used. There are also Limpet Guns scattered around the landscapes that fire at the player. Colliding with a fuel cell, any part of a planet's landscape, being shot, having the attached pod get shot or hit a wall, or still being on the planet when a reactor reaches critical will cost the player a reserve ship, and the game will end when there are no more ships in reserve or the player runs out of fuel.

Fuel pods can be beamed up via the player's tractor beam to add to their fuel level, and also helping the player, at times, are nuclear reactors in each level. Everything on the planet is nuclear powered, which, if the player shoots a nuclear reactor, if there are nearby Limpet Guns, it will disable them for a time; the more times the player shoots a reactor, the longer the guns will not fire. If the player shoots a reactor 14 times though, it will become critical, and the player only has 10 seconds to get off the planet before it explodes. The mission will be considered a failure if the player does not have a pod in their possession, but if the player does make it off the planet with the pod, they will earn a bonus for destroying the planet.

There are also a few sections in the later levels where corridors are blocked by a door, which has a button to shoot in order to open the door so the player can get in and out of that particular area.

Vectrex version
This version is based on the Commodore 64 game.

Controls

 * Move ship left and right—left and right on joystick or D-pad
 * Lock thrust (Hard+ mode only)--button one
 * Tractor beam/shields—button two
 * Thrust—button three
 * Fire—button four

Note: the controls can be reconfigured at the title screen by pressing button two.

Game Modes
(chosen during the attract mode by pressing button one)


 * Normal—this is the default game.
 * Hard +--the Limpet Guns fire an additional weapon that homes in on the player's ship, which will only disappear once being absorbed by the player's shields, eventually dissipating into a wall, or making contact with (and destroying) the player's ship. The player won't receive an extra ship at every 10,000 points like on the Normal mode, but every 20,000, although there is an extra "Perfect bonus" awarded if a player makes it through an entire level without dying, destroying every Limpet Gun, beaming up every fuel cell, and destroying the planet. The player is also able to use an extra control by aiming in one direction while also being able to thrust, and there are two new levels after the usual level six is conquered, although they aren't really like Thrust at all, there is barely any room to maneuver around in them.
 * Time Attack—the player has 75 seconds in order to make it as far as they can as possible. No score, lives or fuel are displayed at the top of the screen though, unlike with the other two modes.

Scoring

 * Destroying Limpet gun—750 points
 * Destroying a fuel cell—150 points
 * Beaming up fuel cell—300 points
 * Mission completion bonus—varies
 * Destroying planet—2000 points bonus
 * Perfect bonus (Hard+ mode only)--varies

Difficulty Levels
There are only six levels in a game (not counting the extra two in the Hard+ mode), which, if the player is able to defeat the sixth level, the game will start over at the first level, but this time around the player has to contend with reverse gravity, which will pull the player's ship upwards towards the sky, not the other way around.

If the player is able to get past the last level of the reverse gravity universe, then they will enter the invisible landscape planets, where the landscape is invisible; only the pods, bunkers, doors, etc. are visible unless the player activates their shield (which consumes energy faster). If the player can get past the last level, then they will enter the reverse gravity/invisible landscape levels, and if they are able to get past the last planet there, the game will end, displaying a congratulatory message sandwiched in between two Thrust logos on the screen.

Extras
Pressing two at the main menu will enable the player to reconfigure the controls (button one), watch a demo for the first three levels (button two), and reset the high scores (button three, although that will also lock ZSB back up, which will have to be re-earned if the player had previously accomplished this).

ZSB
This is the unlockable hidden game included with Thrust. After the game has been unlocked, once the Thrust attract mode starts, this third option will appear; pressing button three takes the player to the ZSB title screen, then pressing any button from there starts the game, which is a clone of The Empire Strikes Back, which was released for the Atari 2600 and Intellivision.

In this game, the player controls a ship that must destroy Imperial AT-Ats. There is a base located below the player's starting point that they must defend (which was not shown onscreen on the Atari 2600 version) from the AT-ATs. Unlike with the original where the AT-ATs take 48 hits to be destroyed, these only take 12, although there are no bomb hatches that appear that, with a well-placed shot, can destroy an AT-AT right then and there.

AT-ATs can only take damage in the head, and not anywhere else on its body (except for the legs) like in the original. The AT-ATs also only fire one kind of weapon, rather than the regular shots and the smart bombs from the original, and plus if the player destroys several AT-ATs then they can fire several of these shots at once. Also, the AT-ATs will start jumping after several of them are destroyed.

There are no pit stops for the player to repair their snowspeeder with, along with no Force included here either like with the Atari 2600 original to make them invulnerable to the enemy.

The player starts off with three ships and will lose one when hit by enemy fire or by colliding with an AT-AT (not including its legs, which the player can again fly through). The game ends when there are no more reserve ships left or if the player's base is overrun. An extra ship is awarded at 10,000 points.

Unlike with Thrust, the high score is not saved once the Vectrex is turned off, and there is also only one game, no over a dozen of them with several variations like with the Atari 2600 original.

Controls


 * Move ship (up and down only)--joystick or D-pad
 * Reverse ship—button two
 * Thrust—button three
 * Fire—button four

Scoring


 * Hitting an AT-AT—30 points
 * Destroying an AT-AT—100 points

Trivia

 * Thrust made sense to be ported to the Vectrex, as with many versions of the original, the graphics showed outlines of objects, imitating a vector graphic look.
 * This is not the first homebrew version of the game, as several versions were also made for the Atari 2600.

Links

 * Ville Krumlinde's Vectrex pages (author of Vectrex version)

Even though this is a full article for the Vectrex homebrew, this is still a stub due to barely a mention of the other versions, which should be included so this could be considered a complete article sometime in the future. (see info box for other released versions)