[Tried getting sprite 36096?]

You say this happened while building in a server but your screenshot shows you in single player?

[Error connecting to some servers, problem with sprite 65535]

Your voices were heard I submitted a PULL REQUEST that seems to solve this but am looking for testers.  btw does this happen with uncap fps off?

[Volume Adjustment.]

There is actually a master_volume config option but there is no UI slider for it.  I think it was decided to not have one because the slider for sound controls pretty much everything except music, so it is easy enough, and having 3 volume sliders would be confusing.

[Multiplayer Protocol]

It is really simple,

2 bytes for packet size, 4 byte uint32 for command type, and the rest depends on the command.  Also, everything is converted to network byte order (big endian).

[How Did YOU Find Out About OpenRCT2?]

Was adding my game Silencer to open source recreations on wikipedia and noticed there was Rollercoaster Tycoon.  I like this game and it is 2D using SDL as well so thought to check it out.  There were lots of bugs when trying to play and my progress would be lost when it crashed, this caused me to submit fixes on GitHub.