I'm sorry, it can be tricky before I make a proper mac application out of the game, but haven't gotten around to it yet.
You can try:
Double clicking the "RunOnMacScript.sh"
or
Open the terminal
type: cd [path to SyxProto001.jar]
(replace [path to SyxProto001.jar] with the path to it). You can also write "cd " then drag the jar into the terminal window and drop it. You'll have to remove the last part or the path (SyxProto001.jar) hit enter
type: java -jar -XstartOnFirstThread SyxProto001.jar
This should work for 90% of all mac users. I hope it does for you.