Ah, another who falls in on the middle of Alternative World, completely missing the major OAV plots.

Well, not completely. I remember when I did that at Moogle Cavern -- "demo" El-Hazard -- that was the first three eps in RM format. (Deliberately stopped before things actually pick up, although maybe better showmanship would've come from four, but I probably shouldn't have been doing it anyway.)
Oh well. The [full] OAV is
highly recommended. And really required to get a full feel for everyone before Alternative World gets going. Then you can at least appreciate things like what happens between Jinnai and Shayla in AW #4, which is an absolute hoot for anyone familiar with them.
