Google released a standalone Slides application for Apple iOS devices. The app joined its already available Docs and Sheets relatives in the App Store.
As expected, Google Slides for iOS allows you to sync your spreadsheets with Android devices, as well as laptop or desktop computers. All you need is your Google ID.
Offline editing is available too. Your work progress will be saved to the cloud once you go back online. You can also edit and update already Microsoft PowerPoint files.