Threshold

The Good
In Threshold, your objective is to clear each wave of enemies that are flying above you, and once you have accomplished this, you proceed to the next wave. As with most shoot-em-ups at the time, enemies fire their lasers at you. It's easy to know when to dodge the lasers, but there are twice as more lasers fired at you then there was in Space Invaders so this could be difficult to do. Also, the more waves you complete, the more berserk enemies are. On later waves, a few enemies will try to dive-bomb you, and you lose a life if you don't act quickly.

There are some unique features that are worth noting. During the game, you will also have to keep an eye on the two bars on your right. The first one tells you whether your laser is overheating. Once this bar is filled with blue, a warning will appear on screen and you won't be able to fire until the bar is half-blue. The other bar, the fuel gauge, slowly depletes over time. I'm not sure whether you lose a life if it gets empty; I haven't gotten that far. The mothership appears after three or so stages to refuel your ship. The more fuel you have remaining when it arrives, the more bonus points you get.

Graphic-wise, the sprites are drawn nicely. Most of your enemies you will be dealing with look like shapes such as cubes, lines, and hexagons. Out of the sprites, I like the mothership, which is drawn nicely and what's funny about it is that it has frog legs sticking out of it. The backdrop consist of a scrolling starfield, giving you the impression that you are actually fighting in outer space.

There are some good animations. Although the enemies appear to be a bit jerky, this is what it was like in games around its time. There are a number of your ships between the two bars piled on top of each other, and I like the way the ship at the front moves up and goes out of sight, only to appear where your last ship was. Very neat.

Controls are simple, and reflect those found in other arcade games of its type. Moving the joystick left and right moves your ship in the appropriate direction, and the fire button fires your laser. In terms of replayability, there is an urge to have "just one more go" as you are always trying to beat your previous high score.

The Bad
There seems to be nothing wrong with the game itself.

The Bottom Line
In conclusion, Threshold is an excellent shoot-em-up, in which you move your ship left and right and shoot enemies that are a distance above you. The gameplay is different to the ones around its time because you need to make sure that you don't get trigger happy and bang your fire button every second. The graphics and animations are good, and it is easy to learn the controls. If you want an alternative to Space Invaders, then have a go at this game.