My translation attempt:
Oh, you came to look too? There's so much at this gallery [??] [Attempt 2: There's so much to see] [Attempt 3: So many people are here to watch]
The Kaiou Middle School Go Club is at a top level, so it would be a loss if you don't look.
I am wondering if maybe there is some Japanese usage of gallery that I am missing?
3: Spectators for golf, tennis and so on. Also, a place where spectators gather.
If that's the case, then I think my attempt 3 is on the right track but I am not sure.