Programs compiled with the Roadsend Compiler are designed to behave the same as programs run in Zend PHP version 5.2.x. For the latest list of known compatbility issues, please see the wiki page.
The original implementation of PHP was designed to be interpreted and run from inside of a web server. The Roadsend Compiler provides many features, such as a built-in interpreter, that help ensure that your PHP code will work no matter what. But there are many new features, such as separate compilation, an integrated standalone web server (see Online Web Applications), etc., which provide significant advantages, and help move PHP toward the new paradigm of a general-purpose compiled language.