This looks like a good way if not only ensuring that things fall slowly, but also ensuring that they fall in the proper orientation. Gravity bombs typically use fins at the back for this purpose, but that makes them actually turn into the wind by pushing the back of the bomb in the direction of the wind. Smaller fins combined with some drag provided by such a parachute as this, could help gravity bombs be more resistant to winds, while ensuring that the fuse stays pointed down.

I want my landmines to fall slowly, directly and land in a specific orientation. I also want to keep the cost low so that I can distribute a whole lot of them.

You do when you're flying low and you need to escape the munition's effective radius.

Retarded bombs are slowed with a variety of mechanisms, from spring-loaded airbrakes to inflatable ballutes to parachutes. Fuzing can range from superquick for conventional bombs to extended timers for nuclear weapons, all depending upon the application. These parachutes would be great for low flying drone bombers as well as munitions that are highly attitude-sensitive (such as those with improvised fuzes).