Note! This review was written for a previous version of this file!
Trigger is not a side-scroller in any way. All you can do is move your character up and down on the screen and shoot the enemy that moves to the left. Unless you imagine that the enemy is staying still and your character is moving, this is not side-scrolling (there is no visible background). Also, after a few seconds of playing the game, my calculator's screen faded and when I pressed [On] it would say Ram Cleared and then turn off. I had not gotten any low battery messages so I do not think that low batteries caused that to happen.
About the actual game, it was not innovative in graphics or gameplay, since there are better BASIC games of the same theme (where a ship comes down and you have to shoot it). There is no documentation of the purpose of the game in either the actual program or the readme. So, I would not advise anyone to download Trigger, since it might mess up your calculator and there are higher quality BASIC games with identical gameplay.