ID:1473794
 
Name some game developing platforms with multiplayer support similar or better then BYOND's current multiplayer support.
There really aren't any that have drop-in networking support that don't require a level of programming that isn't a barrier to entry for most the folk around here.

BYOND's the only one that I've seen that really tackles the multiplayer issue without expecting you to write your own networking logic.
eclipse origin seems to have multiplayer support built in.
I haven't messed with it too much though.
Be sure to consider all platforms (e.g iPhone, PS3, Xbox, OUYA, Browser Based-HTML)
In response to Sir Quizalot
You're pretty much stuck with writing your own networking logic on any platform.