I'd be interested to see if you followed a tutorial or you just made this by yourself? Or maybe you could make a tutorial for Doom-like enthusiasts? Or the best solution is sell some engine with examples in the store :)
Thanks for the kind words.
A lot was derived from picking apart the 3D demos then adding where necessary. I don't think I've reached any definitive approach to this type of game in Construct so I'll have to keep hacking away at it, most likely in a sequel or follow-up.
I see you mention "corner sniping" in your comment on the Arcade, but did you get to the third level with the armored ghosts? That's supposed to be a surprise for the corner snipers. And, yes, "better enemy AI" is high on my "to do" list.