For the past year, a group of teens in Nigeria called the Critics Company have been uploading short sci-fi films to their YouTube channel. Using a smartphone with a busted screen, makeshift equipment, open source 3D tools like Blender, and green sheets hung on walls, the self-taught group has produced some professional-grade special effects. Check out this 10-minute short they uploaded in January, Z: The Beginning.

Here’s a breakdown of how they did some of the visual effects for their short called Chase:

The group has attracted some media attention; here’s a news report with some further behind-the-scenes details (see also similar reports by Reuters and Al Jazeera):