Looking back at it now, I think it's much worse than it could have been in 1990. Camera work is like a Kentucky chicken farm home-movie about Fido, the family basset hound, who celebrated his 5th birthday, and got a bite from the prise winning rooster, filmed with a VHS-C camera. Microphones hang in more times than they don't. The shadows cast by the crew or the lamps, or whatever that has nothing to do with the given scene occasionaly hang in to the picture.
Major editing errors occur very often. For example: the baboon bangs on the door, trying to break it in. On the other side two teenagers, looking like extras from an early season starsky&hutch episode, are pulling it towards themselves, trying to stop the baboon from opening it. If this was in real life, the baboon would break through the doors like a speeding locomotive, Neo style.
Another blooper is that this whole stuff is supposed to take place in 10+ storied building. At the start of the movie, we see the big block, OK. But in the last quarter of the movie we see the building again from the outside, (this time at night) and just above the second floor we can see the underpart of the drain pipes. This is way beyond anything I've seen.
There are no special effects, the monkey looks like the blood thirsty rabbit from Monty Python's Holy Grail, except it's more shabby and dirty, reminding you more of a microphone boom than any kind of animal.
I was bored to death by this movie from the first frame to the last. It's not scary, it's not exciting, it's not dramatic, it's plainly the shame of every movie maker.
It's bad. -4 out of 10.