EasyRPG is a project to create a free (as in freedom) Role Playing Game (RPG) creation tool.
The project consists on several tools and resources:
It is inspired on a commercial product called RPG Maker.
The Editor is an application with a user interface to design roleplaying games.
It consists on:
The Player is an application to run games made with EasyRPG Editor.
Also it can play RPG Maker 2000 and 2003 games directly (RPG_RT.exe equivalent). This is the main feature in development currently.
EasyRPG Player is very portable. This allows to play games in a lot of systems: GNU/Linux, Windows, OS X, video game consoles and mobile phones.
The original RPG Maker software is not free. RPG Maker includes a shared material library with graphics and sounds, used by most games made with this software, called Run Time Package (RTP). This material can be distributed only with games made with RPG Maker and only by their customers, so these games are depending on a material distribution only available on Japanese Windows Platforms in the case of RPG Maker 2000 and 2003.
So if you are using RPG Maker and you want to play a game made with RPG Maker 2000 and 2003 which they are depending on RTP files, you need a RTP replacement due to license restrictions in the original RTP.
To learn more about RTP replacement you can visit the rtp-replacement development page.