One of the best hardcore games of all time.
First of all, this game is very very original and unique. The game world is incredibly huge, in fact so huge that i won't even try to describe it, you have to see/play/experience/live through it yourself.
The fact that DE was released in 2000 seems unreal, it feels like developers from 2100 travelled to 1998 and did their best to deliver DE with the technologies they could find and use in our time. And that leads to the big irony of DE -
Its built on Unreal engine hehe. Unreal is a classic shooter, which means that there are very few gameplay and gameworld features beside wandering about and shooting enemies, whereas DE is a complete opposite, so it felt really weird when i realised that it was Unreal engine. Of course, it is HEAVILY modified.
The only drawback that you can find in DE is the action part, it feels kinda lame, either its the stiffy and fast animations or something else, but boy is it satisfying when the tough enemies and bosses go to pieces after you feed them a rocket, no matter how unrealistic the going to pieces looks in action. Now that I started thinking and remembering, the nano-sword action is satisfying as hell too.
Another thing worth mentioning is the awesome level design, its better than i have seen in any other 3D game and i have seen many over the last 11 years. The level design + the gameplay + the story + the atmosphere come together and suck you in like no other game.
If you haven't played DE you must, because this game is a fantastic once in a lifetime experience that no other game will deliver. There isn't really even any other game you could compare to DE. Just get and play it and you'll see what i mean.