The Gyroscope app does exist for Android. However, for the best experience we recommend using the iPhone version.
Many of the features are supported on both platforms — like mood tracking, food tracking, coaching, etc. — but the ecosystem on iOS is much more stable and well-supported.
On Android, more manual entry may be required, while on iOS things can be more automatically synced and detected in the background.
For more details about each device and possible sources, check out the full Hardware Guide.