How to play Threshold online
- Fly your ship: arrow keys, in any direction within the lower half of the screen
- Fire your phaser: Space bar
- Start a new game: F12 (the console’s Reset switch)
- Choose a game and one or two players: F11 (the console’s Select switch)
- Straight or homing alien missiles: F4 (Player 1 difficulty) and F9 (Player 2 difficulty)
- Save and load your progress: Ctrl + 0–9 saves to a slot, Alt + 0–9 loads it
Gameplay
You patrol an unknown part of the galaxy when alien ships open fire. Each wave has six attackers, and there are 11 different waves. You lose a ship if an alien or one of its missiles hits you, and the game ends when all three of your ships are gone.
Your phaser has a useful trick: if you press fire again before your last shot hits something or leaves the screen, the gun fires again straight away. Tapping the button quickly gives you a short-range burst of rapid fire.
Speed matters. A bonus gauge in the lower left corner starts each wave at 3,200 points and drains as time passes. Whatever is left when the sixth alien falls is added to your score, plus 50 points for every wave cleared. Each alien is worth more the further you get:
| Wave | Points per alien |
|---|---|
| 1 | 50 |
| 2 | 80 |
| 3 | 100 |
| 4 | 130 |
| 5 | 150 |
| 6 | 180 |
| 7 | 200 |
| 8 | 250 |
| 9 | 300 |
| 10 | 400 |
| 11 | 500 |
You get an extra ship at 20,000 points and another at 40,000, up to a maximum of three. From 40,000 points on, the aliens always fire homing missiles, whatever the difficulty switches say.
Game variations and switches
There are three games for one or two players. Oddly, the numbering runs backwards: game 1 is the hardest, game 2 is moderately hard, and game 3 is the easiest. The difficulty switches decide how the aliens shoot. In position A their missiles fly in a straight line; in position B they are guided missiles that change course to chase your ship.
Tips
- Start with game 3 and switch A. Straight missiles are much easier to dodge while you learn the attack patterns.
- Move up to attack. Flying closer to the aliens and tapping fire quickly makes the most of the rapid-fire trick.
- Drop back to dodge. The bottom of the screen gives you the most time to see missiles coming.
- Finish waves fast. The bonus gauge can be worth more than the aliens themselves in the early waves.
The story behind Threshold
The idea came from Sega’s arcade game Astro Blaster. Ken Williams, the co-founder of On-Line Systems, played it in a shop and phoned Warren Schwader about it. Schwader later said he did not try to copy Astro Blaster detail by detail, but wanted to capture the feeling of always finding new creatures. The Apple II original took about two months to write, and it was also released for the Atari 8-bit computers, the VIC-20, the Commodore 64 and the ColecoVision.
The 2600 version drops the computer original’s warp drive but adds free vertical movement. It won a Certificate of Merit at the 1983 Arcade Awards, and JoyStik magazine gave it four stars out of five. Tigervision also brought two other On-Line Systems games to the 2600, Marauder and Jawbreaker.
