There are a lot of people who are hostile to any new crypto-currency, usually because of their vested interest in previous currencies. They tend to audit any new currency's code, looking for things that can embarrass the developers. There's a very good chance that any back door or serious problem would be widely publicized on sites like the Bitcoin forums.

You can certainly audit the changes yourself. Find the closest trusted code base (the one the code you're trying to evaluate is based on), and run a diff. Then look closely at all changes.

Alternatively, you can rely on the wisdom of crowds. Just wait at least a week or so before accepting any updates published by the development team. And search forums likely to be hostile to that project, such as the Bitcoin forums.

If you're competent at coding my best advice would be to go through the code. Without knowing how it's done it's hard to say what to look for.

It's built from Multicoin - I use Tenebrix and have had no trouble. On top of that I have not heard of an issue of this kind.