Question: I'm looking for a game engine that allows me to build multiplayer games quickly and easily.

If you want a game engine that lets you build multiplayer games fast, the Photon Engine is a great option. It comes with a cross-platform backend service that supports Android, iOS, .NET, Mac OS, Unity 3D, and Unreal Engine, with state synchronization and deterministic performance. The service also includes real-time APIs for matchmaking and room management, voice and chat support, and cloud hosting with low-latency servers in all major regions.

Another powerful option is Dreamlab, which uses modern web technology to make game development easier and concentrate on game design instead of asset creation. It supports real-time multiplayer, AI-generated assets and web-based development. Dreamlab also has a web-based interface, real-time collaboration and the ability to publish games as standalone web apps or Discord Activities, so it's a good option for building fast multiplayer games.

If you need a broader set of services, check out Microsoft Azure PlayFab. The service lets you build and operate live games on Xbox, PlayStation, Nintendo Switch and other platforms, with features like cross-network identity, matchmaking and real-time analytics. It also includes tools for live operations, content management and engagement and retention, so it's a good option for game developers who want something more powerful than a simple game engine.

Last, Vivox is in-game voice chat software that's integrated with Unity and Unreal engines, with support for cross-play compatible chat and other features like 3D Positional Voice Chat. The service is designed to improve multiplayer gaming by letting players communicate in real time, so it's a good addition to your game engine.