Kaizena now supports adding audio feedback on Google Presentations. Kaizena is a tool that integrates with your Google Drive account. With Kaizena authorized to access your Google Drive account you can highlight portions of your students' work and add voice or text comments to it. Until today you could only leave voice comments on Google Documents, now you can leave voice comments on Google Presentations too.
To use Kaizena to leave voice comments for your students your student should share their Documents or Presentations with you. Once they have shared their Documents or Presentations with you, open the shared file through Kaizena. With the shared file open you can highlight a portion of a slide then click the microphone icon to record your voice comment. Your students will see the comments after you have saved them. Greg Kulowiec outlined the process in this post. You can also watch the video below to see how the new feature works.