This opening has so many names in it, it sounds like a law firm. I don't know much about the Falkbeer (or chess in general!), but anything with the name 'Marshall' in it gets my attention.
I think the move 4.Qe2 is sort of old hat, with 4.Nc3 being more popular now. I was surprised to find this uncharacteristic loss of Alekhine's, Alekhine Alexander A vs Johner Paul F , where white tries 6.c3. More common now seems to be 6.Nf3. Anyway, I lost a bunch of games playing the black side of this thing, but did manage to eek out a few wins. This one was pretty interesting, with 16...Bb4 sort of a zwischenzug.......
I also found this strange idea in the Nc3 line, ...Bb4!?