M.J. I am glad you asked.
1) It will be compatible with D&D stuff.
2) Standard 3d6 Attribute roll up, but only 3 attributes Body, (STR/DEX) Mind (INT/WIS), and Will (CON/CHA).
3) Characters will also gain abilities with each level. These add bonuses to doing things and allow each character to be built uniquely over the course of play.
4) It will use ascending AC which acts the "to hit" target number in combat
5) It will use classes, hit points, standard SRD spell lists and monsters.
5) Magic will work a bit differently in Peril. No Vancian magic system, but something different instead. In a nutshell your MIND attribute is your target number. To cast a spell you roll a d20 and add the level of the spell being cast to the d20 number rolled. Compare the resulting sm to your MIND attribute.
If the sum is equal to or under your MIND score-the spell is cast, and can be cast again! If not the spell failed and cannot be cast until 8 hours rest and study of the spell again.
In the end its my own spin on creating an easy, fast and fun entry to playing the grand old game while allowing use of a lot of great stuff out there. I want my "Basic rules" to come in at 24 pgs and the free Pocket version will be 8 pgs.