OHRRPGCE Licensing
Starting with the ichorescent stable release, the OHRRPGCE changed its license from GPLv2+ to Dual GPLv2+ & MIT License, meaning you may use and redistribute it under either of them. This was done with the unanimous consent of all OHRRPGCE developers (Contributors/Relicensing), and after replacing a small amount of 3rd-party code.
The games you make with the OHRRPGCE do not have to be under either the GPL license or the MIT license. You can distribute your games any way you like, including selling them. If you include a copy of the Game player with your game (as you should!), you should be sure to also include a copy of LICENSE-binary.txt.
Dual license[edit]
The dual licensing change facilitates special-case porting to closed platforms such as some consoles where the GPL is not acceptable to the console manufacturer (for example because it requires certain user rights that they don't provide to players, or because system interface code must not be publicly released), while also publicly demonstrating our respect for the copyleft principles of the GPL. We continue sharing the source code in the same way and spirit we always have. We have worked to add abstraction layers to the source code so that private console code can be contained in separate libraries (e.g. "blackbox" for the first console ports) without needing a private OHRRPGCE fork. Thus far, this has enabled all console-port-specific changes made to the engine to be released under the GPL/MIT too.
The GNU GPL (General Public License) is a "copyleft" license. The OHRRPGCE's source code is released under this license, either version 2, or (at your option) any later version, or optionally the MIT license.
Basically the GPL means that not only can you freely use and redistribute the source (or compiled binaries), you are also allowed to make changes to it, as long as you promise to make your changes available to everyone else with all the same freedoms that have been promised to you. (In other words, any derived works must also be released under the terms of the GPL.)
If you need to create a port onto a platform where GPL licensing is not possible, you can create your fork under the MIT license. If you wish to make a GPL-only fork, you are free to do that also. We still greatly appreciate any contributions back to the dual licensed upstream. In order to contribute your changes to the official OHRRPGCE codebase you need to provide/license them under dual GPL/MIT.