At some point, it needs to be considered what's worse: terrible looking CGI creatures or terrible looking CGI volcanoes. Both are disastrous, but not for the reasons intended. That said, Magma fares better than expected given the effects and re-used set pieces.
The set up is basic and quick. Volcanoes erupt, people quickly form to figure out how to stop it, and then execute the plan. Through this, you'll dive into some deep (for Sci-Fi Channel) characters that elicit a small emotional pull. The scenario is no more dire than any other "human extinction is probable until we find a way to stop it" disaster movie. You'll know what to expect.
Science is loose at best, and the film is wise to stray far from offering too much explanation. All you need to know is that lava makes for an easy special effect, and that means you'll see plenty of it bursting from the Earth's core. The fix is completely implausible, but then again so is the scenario in the first place if the National Geographic Channel has anything to say about it.
The film's biggest problem is the ending. It sets itself up as a near-finish, and you would expect this to become a film split into a few parts. Nothing seems to be going as planned; yet the credits roll a few minutes later. It all happens too quickly, and the massive, global destruction supposedly caused is only shown on TVs, and even then, you only see the volcano. The few deaths that do make it on film don't compensate for the millions viewers are only told about.
There is some energy to this one, unlike the countless other lifeless Sci-Fi Channel features. It's paced well, and the acting from surprisingly talented Amy Jo Johnson (yes, the pink Power Ranger) is believable enough to carry the action. The rest of the cast keeps pace.
No more ridiculous than any of the major Hollywood productions, Magma doesn't replace other (and better) volcano destruction movies, but makes for a brief, tolerable diversion. There seems to be a little care put forth in this one, and the budgetary restrictions are the only reason it feels so small. These rare, somewhat entertaining Saturday night movies show us that someone at the network does care, at least a few times a year.