" I am unable to connect. I always get 'Not connected to game server' "
Windows 7 has a bug with network adapters which is fixed by an update.
Update your Windows with latest updates from Windows Update.
Video tutorial: watch
" Online play is very slow. "
You need to play against players who have low ping to you.
<50ms is optimal for full speed.
<100ms is still playable but slower.
Anything over 100ms is unplayable.
" I can't see my ping. I only see the pings of others. "
The connection betweens players is direct, without a server in between for minimum latency.
So the software shows your ping to each of the players. The ping to yourself would be zero.
" I have a question which is not addressed here. "
Go to the Online Lobby and contact the developer taco / kebabsorm1.