For a movie with a close-to-nothing budget, this is surprisingly good. Special effects are somewhere between cheap and nonexistent, the whole movie is carried by the actors and the script.
But both the actors and the script are good. George Wendt (as Charlie) is a John Goodman-lookalike and uses that very well. Shanna Reed (Rhonda) is his happy tourist wife, if possible more gleeful about their backstreet adventures. Anastasia Sakelaris plays their beautiful daughter Daphne, also really well, and Christopher M. Brown is the "straight man" Joseph, the nice black guy who tries to understand what is happening around him. Joseph is a particularly vital part, the straight man who gives us a normal person point of view to the events, and also the character who benefits from the aliens. These four actors are the backbone that carries the film.
The obvious B-movie status and low budget limits the possibilities, and sometimes the lack of effects is disturbing. But most of the time it doesn't matter too much (as long as you are prepared for it). We see some blood, and hear some profane language plus see some semi-nudity, but I was happy to see that neither were over-used but used for a reason. And this is one sign of the good script. It doesn't need to use cheap unmotivated sex and under-the-belt-jokes, it uses these themes sparingly in logical and therefore funny ways.
I find it amusing to compare the movie to Predator 2. The basic plots is the same, aliens come to the slum to hunt some wildlife. But from that point, they are totally different. Imagine a Predator posing by the victim, smiling, being photographed with a cheap tourist camera. And imagine it walking around in the open, looking like an average tourist. Hard to imagine? But there you have the basic premise. Same... but totally different.