For people who are not familiar with the term, “Serious Games” are computer or video games that are created for sole educational purpose, and that is the primary goal for our project Gas Zappers. Richard Carey from Serious Games Source analyzes which game engine is the most comparable to the special needs of Serious Games.

Serious games and educational simulations are an unique product category with functional requirements that are different from platform and casual games, MMOGs, and drill–n-skill learning games. The gameplay itself is only the tip of the iceberg: hidden out of sight is an engine the player doesn’t see. (Note in this article the term “engine” is meant to be inclusive of the middleware, networking, client software and other components used to deliver the desired user experience, whereas “platform” refers to the combination of hardware and software required to use the product).

As an emerging market little has been written about the best engines for building serious games. This lack of transparency makes it difficult for publishers to choose development partners, and for developers to scope serious game projects and determine the best tools to use.

Full Article Here

More resources here:
Serious Game Engine Comparison
DevMaster.net database of game engines
SIGGRAPH database of game engines
Game Engine Features & Possibilities