These do look impressive but, for me anyway, most of the fake 3D depth is too extreme.
The floor in the opening room, for example, looks almost impossible to walk on:
and, of course, that doesn't sit well with the edges of steps either:
It also leads to difficulties where walls meet:
And the details on this door are almost deeper than the width of the door sector:
I'm not really sure what is going on with this vine/moss - is it meant to stand proud of the wall, or is the wall going in at the edge of the vine?
Again, I see what you were going for but the effect is just too extreme IMO - especially as this texture is used on both floors and ceilings. On ceilings it might be OK; on floors it's too much IMO.
The water is one of the less extreme examples but it still looks a bit too choppy and "strange, rounded viscous blue stuff" rather than water.
So, yeah, sorry to sound so down on this because I can see that a lot of work has gone into it and the initial impression is definitely "Oh wow! That's amazing." but when you start looking more closely, I just think that the depth effect is way too overdone on many of the textures. IMO, it needs to be more subtle from a purely aesthetic POV anyway but given that Heretic has a limited texture set and that the textures are used in a variety of ways and places, effects like this need to be subtle because they need to allow for the wide and varied ways in which the mappers have used them.