Downloading Slidium 1.1 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. This software for Mac OS X is an intellectual property of Neomobili. The program lies within Design & Photo Tools, more precisely Presentation Tools. We recommend checking the downloaded files with any free antivirus.
From the developer:
Slidium offers an easy way to create a beautiful markdown presentations. It offers an enhanced version of Markdown, with an intuitive syntax for charts and graphs. The application comes packed with modern build-in themes. The themes can contain different layouts to fit with each slide contents.
You may want to check out more software for Mac, such as Vvidget, S90 ES Mix Editor or Toon Boom Storyboard, which might be similar to Slidium.