Threshold is a fun little shooter from Sierra On-Line which falls into the briefly popular category of Astro Blaster clones. Astro Blaster was a hit Sega arcade game which was widely cloned on home computers at the time due to it's simple but fun gameplay. One of the best known clones was Activision's Megamania, but Threshold was clone of choice on home computers due to Sierra's reputation for quality games. Although Sierra produced cartridges under their own label for other systems, they chose to partner with Tigervision on the Atari 2600. Jawbreaker and Marauder were also released as part of this partnership.
As mentioned above, the concept behind Threshold is
simple. The player controls a ship at the bottom of the
screen which must shoot wave after wave of enemies before the
fuel gauge (called the bonus timer in the 2600 version) runs
out. It's interesting to note that the 2600 version is
missing the heat gauge which would increase each time the player
shot. Once this gauge was maxed out the player could not
shoot until it cooled down. This kept the player from
continually doing rapid fire and added another bit of challenge
to the game. It's unknown why this was removed from the
2600 version, but it makes the game a lot easier.
Each of the eleven waves of enemies in threshold has a unique shape and behavior. Some enemies like to dive bomb you from the top of the screen, while others move sideways across the screen and only shoot at you. Some enemies stay in a tight formation while others appear seemingly at random. One of the things that keeps players coming back for more is hoping to get to the next level and see a new enemy.
At it's core Threshold is a simple but fun little
shooter, witch decent graphics and quick fluid gameplay.
Threshold ranks among one of the better Tigervision titles,
which isn't surprising given its pedigree. One of
Threshold's more devious quirks is that the default game
variation is actually the most difficult. Most titles put
the middle or easy level difficulty first, but Threshold does
just the opposite. So if you've ever wondered why the game
was so tough, try selecting variation 2 or 3 instead.