From Hellgatewiki.com

Flagship Studios has a definite design philosophy that they brought along from Blizzard North. They want to make games fun, easy to learn, exciting to play with friends, and long lasting thanks to randomization.

Design Theory

Bill Roper talked about their plans, in a general sense, in numerous early interviews, back before Hellgate: London had even been announced yet.

Don't be afraid to throw out something that doesn't work. So often developers become slaves to a massive design document that was written in the first 3 months of a project that they are afraid to cut something from the game that just isn't working. You have to be adaptable in your development process and be willing to adjust to make the game as fun as you can. If you always keep the core vision of what you want your game to be in mind, you can be flexible to achieve that goal, even if it means throwing something out that you thought was going to be brilliant.
--Bill Roper, January 16, 2004 Behind the Veil interview.

Design documents are nice, but don't get carried away. Work fast, think on your feet, and change things that aren't fun.

We usually will write a 1-2 page white paper and then everyone works on the ideas that are there. The team may change those ideas or modify them, or we may find we have something that works but it doesn't make sense in the game. Again, we argue passionately about what goes into the game. It's all about keeping our focus on the game.

Other teams will spend weeks or months on their design document. The disadvantage to that approach is that they then become hesitant to make changes after they have so much time invested in the original design.
--Bill Roper, May 18, 2004.

Get the game going and let it guide its own design through play testing and natural selection.

One of our philosophies of design is to get the game up and running as early as possible, keep it at a constantly playable state, and then constantly iterate on what's there. Although this process takes a very specific mindset and dedication from the development team, we have found this to be the best way for us to create and balance an RPG.
--Bill Roper, October 15, 2004

Game Complexity

Blizzard games are noted for being easy to learn, but containing a great deal of depth which leads to long term play and replayability. Flagship aims to make Hellgate: London along those lines. It's not a revolutionary game; it's a fusion of many different game types, with an approach original enough to interest most anyone.

I'm not here to fool anyone into thinking our game is as complex as SWAT 4 -- Irrational is one of my favorite developers of all time, BTW -- nor am I going to lie and say we're as approachable or heavily reliant on tactics as Silent Hunter. That would be plain silly of me. In fact, I have to say the exact opposite. Hellgate, in many ways, is very much like Diablo. If you find that type of click heavy gameplay unsatisfying, there's a pretty good chance you'll not be overly excited by our game.

That being said, Hellgate still has quite a bit of diversity to keep it from feeling repetitive. Like any action RPG of worth, we offer over a hundred distinctly different base weapon types with multiple versions of each type. And, they can all be modified with multiple categories and types of add-ons. There're also over 30 base monster types in Hellgate, a dozen distinctly different environments (each with noticeably different subtypes and schemes), and we have around 30 skills per character class. Of course, we also have a freaking ridiculous amount of armor and items, because shit like that is pretty much mandatory these days.

So basically the combination of weapons, items, mods, enemies, environment types and skills in a totally randomized world with predetermined "interest" set pieces is what most of our fans find exciting. We also apply all this content to cooperative and competitive multiplayer modes. But... Our fundamental gameplay focuses on rapidly using a combination of skills and weapons in different groupings to best monsters of varying difficulty. The mechanisms that govern this action are not reliant on conventional definitions of skill, however. That is, playing Hellgate doesn't require much the way of planning or reflex, and so gamers with tastes like your own may find our title wanting, but then it's impossible to please everyone all the time, you know?
-- Ivan Sulic

How Should Hellgate: London be Played?

Fast and furious.

I really like the sense of empowerment associated with plowing through waves of demons. The action is pretty cool when I hotkey certain skills with certain weapon groupings. In this way it's possible for me to change through three groups of six weapons with multiple mouse button bindings and no less than six separate skills just using the mouse and three function keys (and without ever going into the inventory, of course). So basically I run around like a maniac switching up my attacks and skills and weapon groupings and pretty much obliterating anything that stands in my way. I enjoy that.
--Ivan Sulic