It's nice as an early entry in its genre, but worldbuilding and character development is extremely lacking. The entire thing is very rushed, which is the case for the manga it's based off of as well. I would have liked to see this paced as a TV series instead of an hour-long OVA. The basic premise is interesting (though nothing we haven't seen before) and the atmosphere is nice, but the OVA simply doesn't have enough time for the story it's trying to tell. It's a charming little movie that's worth a watch, and I personally enjoyed it, but don't expect anything super deep and fleshed-out.
The story for this movie is minimal, at best. It's pretty straightforward and not really the focus of the move. It provides the backdrop for the real meat of the movie: fighting, and lots of it. It's not gory, since most of the on-screen deaths we see are either explosions or androids, but there is a lot of violence. The story doesn't even really conclude at the end! If someone was looking for an interesting look at dystopian society and the nature of humanity, they would have to keep looking, as they won't find it here.
The animation is pretty bad, even by 80s standards. I tend to prefer old-school animation because I find its coloration much more saturated and its backgrounds more detailed, but this movie misses the mark by a mile. The character designs are not interesting, nor diversified. There are about 4-5 character types total, and even between them, look fairly similar.
The sound is, in a word, CHEESY. The music is heavily reliant on synthesizers, and the characters have boring dialogue. Nothing they say is really all that interesting or surprising, and even the voice actors seem bored by their own characters.
Characters are one-dimensional, at best. None of them go through any sort of interesting developments, and stay the same throughout the movie. Minor characters hardly get any personality at all before they're killed off.
Grey: Digital Target seems like it would be an interesting movie, based on a dystopian society clawing its way to the top and prestige, only to find out there's something amiss in their world. However, it is executed seemingly for the sole sake of lots of fighting. It ends up being quite boring as there are no unpredictable plot twists, and things turn out much the way you'd predict it to be.