Thread:Vorknkx/@comment-3547390-20120228215130/@comment-1496755-20120318115010

Why not :)

I read somewhere that Episode 4 was made from maps that couldn't fit anywhere else. This can explain the borrowing and exceptions that we have been observing.

As a whole, both E1 and E4 can be considered special cases. E1 is shareware and deliberately mixes styles to advertise the full game, whereas E4 is made of "leftover" maps. Therefore, we can expect styles to blur and mix from time to time.