The game is hub based, uses resources from both heretic and hexen and uses a few monsters from the bestiary. I've been learning acs and I've more or less figured out decorate and have made things like ettins that throw flechettes and such. The hub will consist of a castle, a gardens map, sewers, a ruined keep, and a few other areas. I'm not sure if I'll make additional hubs or not. I was planning on having a sort of leveling system where you could find max health ups (via the stamina upgrade from strife) and fragments of them as the game progressed. Further, instead of the tomes of power being one time use items in the inventory, I intend to have them grant a "level" which would up your maximum mana a bit, and depending on how many you had collected to that point a would either grant a permanent upgrade or alternative attack to one of your weapons. Bosses would drop them and pages of them would be scattered in hidden places (collect a number of pages and it gives you full book sort of idea).