Our expeditious series on the Ruy Lopez continues in its brisk way; we're up to episode XXVIII now! There's a lot of material in this episode, as I present no fewer than four variations associated with the Marshall Gambit.
First, there's one final anti-Marshall line: 8.c3 d5 9.d4. Some players might try this rather than an 8th move Anti-Marshall if they want to check to see if Black was only bluffing the Marshall. As it's far less promising than 8.a4 or 8.h3, however, they'd be better served by choosing one of those lines instead, or simply braving the Marshall.
Next, we look at inferior versions of the gambit that Black might try: 8.c3 d5 9.exd5 e4?!/? (the Steiner Gambit); 9...Nxd5 10.Nxe5 Nxe5 11.Rxe5 Nf6?!/? (Marshall's original recipe); and 11...Bb7 (also used by Marshall). The first two are probably clearly better for White (at least!), while the latter is a bit better but still somewhat problematic if my analysis is correct.
But is it? Have a look and let me know! The show is free, as always.