obSESSION(TM) is more than just a Role Playing Game, it is a set of core mechanics designed for use with any setting, genre or game style. The fully expandable rules contained in this book are adjustable for a variety of playing styles and can be used to model any reality that the GM or designer can imagine.
Additional optional rules from Obsessive Compulsive Design are fully compatible with the rules found within, expanding upon rather than contradicting the core rules and ensuring that any optional expansion is usable with any obSESSION game, not just one or two.
GMs and designers can choose the level of realism they desire and balance it against a number of player-friendly options to create the game and experience that they want. By building from a consistent base model of reality obSESSION allows for the rules or settings to be "tweaked" without losing compatibility. It's internal consistency also allows for a minimum of mechanics to cover a maximum array of potential situations and makes "on-the-fly" rules decisions simple.
Add to that the OCD Open Rules Policy and you have an essential tool kit for the creation of game settings or even complete games, whether for personal use or for publication.
obSESSION has been in the pipeline for more years than I care to remember but after a lot of tweaking and adjustment it is finally being delivered into the hands of the public for evaluation. The Beta Editon of the Core Rules is now available on DriveThruRPG.
The obSESSION Beta Edition is a release designed to be used to playtest and improve the system before it's final commercial release. On it's initial release the Beta contained the Core Rulebook, a sample chapter from the forthcoming Simple Fantasy genre supplement and a "Extras" booklet. Purchase of the Beta Edition will entitle you to receive the Core Set when it is released, including the full versions of the Appendices. Over the course of the remaining development the Beta Edition will be revised to gradually bring it closer to the final Core Set. This will involve both the addition of the Appendix material and the removal of the "Extras" and the sample chapter, though some material which originally surfaces in Extras will likely end up in the Appendices.