I really wanted to like this title after growing up with Doom and Doom II. I didn't have the chance to play it when it was first released but when GoG had it, I thought I'd give it a go. I played it on and off for a few minutes after work for about a week, getting to Alpha Labs 3. I put it aside for a few days and then tried to get back into it only to realize I just don't care. Maybe it's just too slow paced, or maybe it's the overall feelings of dread it inspires. Either way, I can't say I recommend it. Hopefully there are some decent mods out there that bring back the original Doom feel.
This is one of the best games ever made. Certainly a "must have" for any classic DOS games self. Now where did that source code get to?