First of all before going any further, I would like to state that Judge Dredd D20 does not "Suck" by any stretch of the imagination. Like all other systems, it has its foibles and its idiosyncrasies, but should not be dismissed out of hand, as I have heard some people do: though I suspect such negativity mostly comes from non D&D players (and those not familiar with the system). Here-say from others can be a dangerous thing.. as anyone playing in a well run game can attest to. A badly run game will usually make the rules `suck`. A well run game will make a system shine. Same game, just different perceptions.
I would also like to point out that if a house system is not originally and specifically designed for a genre of game, does not mean it cannot do so. A prime example might be G.U.R.P.S which was originally designed to be an all purpose generic fantasy rules engine: but which went on to cover games for Science Fiction, Modern (Vietnam to Falklands), Modern Horror, Superheroes, even a Zombie version exists.
Many people just hate D&D.. probably because they don`t truly understand it after the changes took place; when TSR became Wizard of the Coast, and 3rd edition hit the shelves: neither does everyone (I suspect) understand the `open licensing` laws which heralded in the birth of D20 as a universal and unifying engine upon which game hosts could build their chosen game worlds, confident that anywhere in the world, other players and groups would understand the system and be able to join in blind sessions, pretty much at the drop of a hat.
Because Judge Dredd D20 works off a fantasy game system, doesn`t mean it is not a viable game system in its own right. What I am saying is that Dredd D20 works. It isn`t just another flavour of "sh**." When Mongoose chose to go with it, they went with the D20 franchise for a very good reason. D&D 3rd Edition (or D20 if you prefer) was the most popular rpg and skirmish table top game system in the world at the time, and understood intimately by most gamers (there were of course a few who condemned it because they didn’t understand its complexity and preferred the earlier, simpler version of the game - while under the license of TSR). That`s what open license did, it allowed independent companies.. legally.. to write games under the D20 flag: which meant suddenly, you could play all these new and wonderful types of adventures without constantly having to learn new set of rules each time, as all D20 games ran off the same engine (just like G.U.R.P.S).
For those willing to make concessions to their favourite game ethos, and who were willing to make changes to fit these new world genres. Then D20 was like a game host and game player`s Godsend.
The Judge Class was simply the fighter class (verbatim) from the Players Hand Book, and the Citizen simply the Thief class. Yet Mongoose, put a lot of work into making this game work for the new Judge Dredd game, rather than for D&D and D20. Judge Dredd D20 had a lot more scope than the older GW game, which simply wasn’t able to handle things as well. In D20, every stat block could potentially be a skill the players could use in game, and if you roll high enough you could even choose to be a cool Psi Judge. The flexibilities are endless. Best of all you can even play a citizen, a criminal, a bounty hunter, or any other type of non Judge you fancy playing. Even aliens - or fury simians.
Is 3rd Edition D&D my favourite system.. no! Neither is its identical twin sister the D20 system. But does it do a good job at taking a well thought out game engine and utilizing it for an entirely different genre.. oh absolutely yes.
It is true, Mongoose were forced to use a little too much space (for my liking) detailing the D20 mechanics, but in its 256 beautifully rendered pages, it does a simply amazing job at bringing the Big Meg to life: no mean feat when you consider how huge a place it is, with a vast amount of culture and history to describe. But this book not only covers all the necessaries for playing Judge Dredd within a D20 system, but actually spends a good 200 or so pages devoted entirely to background information on the world. Even when its telling you the rules, its simultaneously filling the reader`s mind with lush ideas and accurate world filler information.
The writers of this Judge Dredd book are obviously fans of Joe Dredd and the whole world ethos: and the entire book seems something of a pure labour of love. Covering all the usual suspects and plenty more besides. From time lines, maps, robots, an in depth look at all the various department(s), drugs, vices, diseases, types of food and drink consumed, public games, even a tour of the city (and its many districts), and an in depth “how to” campaign in Mega City One. Of course there are sections on vehicles and weapons, ammunition types.. and all lavishly illustrated. I think perhaps the best section of all are the pages devoted to naming each and every law - and the penalty for breaking each one.