The phrase "decent film" means a movie that is satisfactory or average in quality. It is neither exceptional nor terrible, but falls somewhere in the middle. Full definition
Only one decent film in his catalogue and it is his first one. (filmjunk.com)
I don't really have much desire to see this, I just don't see how they can make a really decent film about this whilst it's still going on. (digitalshortbread.com)
Although not a great film by any means, this is still a pretty decent film that is provides some mindless entertainment value. (rottentomatoes.com)