Similarites between Doom 2 and A&A

[el zee]

I think Doom 2 might have been the base for this game, it might have even been a mod for Doom to start with.

In PICS.RES there are a lot of match ups with doom2.wad,  as far as textures go (BIGDOOR1-7, FLAT5_1, F_SKY1 etc..). Graphics wise there is a similar status bar to doom's.

[Lawstiker]

makes me wonder how "legal" this game was when it was released 

[el zee]

I dunno? All the graphics are different, just the names are the same, but using dooms map format?

[leilei]

The renderer pretty much is similar, slime trails, friction slides, etc. The mapping tool used was DeeP.

The Doom lump names were probably for placeholder, is my guess. Blood and Battlezone similarly used Quake sounds for placeholders before being replaced too, though obviously those aren't directly based off of Quake themselves

[el zee]

Yeah, if you open up the map files in a hex editor, it has a PWAD header, and "deep is the best" written in there too.