Can anyone recommend a php game engine for creating simple games? I'm thinking turn based games where you enter info and then click the submit button. Nothing real time or fancy graphics, just simple strategy games etc..
A game engine is traditionally a GUI. You should just write your own classes for a web-based engine and you can use them again yourself. The whole principle behind functions and object oriented programming is to allow for a class or method to be used again.
as far as i know unity game engine is based on javascript/python. not heard of any engine with php. Atleast you should know python/perl. check these game engines: http://corpocrat.com/2010/09/21/best-free-game-engines-for-game-developers/