Unity3d is a 3D game engine built for cross-platform development
While in college I spent a lot of time creating games inside Unity3D, both for class projects and for my own independent ideas. After graduation, I've been fortunate enough to continue using Unity while at F84 Games. As a Technical Designer, most of my time spent in Unity isn't focused on the core gameplay but instead the surrounding elements such as UI layout or the implementation of minor features. For example I created the Supply Drop 'slot machine' featured in Survival Run and did most of the dynamic scaling of the UI. I also spend a lot of time working on the Android versions of our games. This involves UI modifications, and writing plugins and android specific code for things such as in-app purchasing, and more. I've helped bring iOS games to Google Play, Amazon Marketplace, and the Nook App Store.
All Unity code that I write is done entirely in C#, and the Android plugins that I code are usually done in Java.