> There were a million Doom clones, none of which were as good as Doom.

Sorry to take this on a tangent, but the problem with Doom clones isn't that they aren't as good as Doom, it is that Doom already exists and is known to the audience. If you've had your mind blown by Doom, playing a 10% better version of Doom isn't going to blow your mind again, it is going to merely be a fun experience. Many people won't even bother to try that 10% better Doom clone, since all they'll see is a clone of something they already tried.