Name: Xamarin Studio
Mac Platform: Intel
OS version: OS X 10.9 or later
Processor type(s) & speed: i5 2GHz
RAM minimum: 1
Video RAM: 512
XamarinInstaller.dmg - is the web-installer. It will install all additional packages.
Anyway, you can install everything manually if you want.
Android SDK not included.
Also, there are Xamarin Android Player and Xamarin Profiler.
Don't forget to read README file in "patch" folder
At Xamarin, we believe that great, native mobile user experiences have the power to transform customer relationships and employee productivity. Unlike other cross-platform mobile frameworks that only offer lowest common denominator experiences through UI abstraction libraries, we make 100% of the iOS and Android APIs available through our native bindings. Xamarin developers deliver high performance, fully native experiences and also share between 60 and 100% of their source code across platforms.
Xamarin is the only platform with complete API coverage and deep code-sharing capabilities across iOS, Android and Windows apps, for a total of 2.6 billion devices you can reach in C#. Anything you can do in Objective-C and Java can be done in C# with Xamarin.
More info: http://xamarin.com/studio