You might need an edited function to make weapons able to damage people, though. Or make it so only you can create a minigame:
package NoJets{
function GameConnection::SpawnPlayer(%this){
Parent::SpawnPlayer(%this);
%this.player.setDataBlock(PlayerNoJet);
%this.ApplyBodyParts();
%this.ApplyBodyColors();
}
function serverCmdCreateMinigame(%client,%a,%b,%c,%d,%e){
if(%client.BL_ID == [YOUR ID] parent::serverCmdCreateMinigame(%client,%a,%b,%c,%d,%e);
}
};
ActivatePackage(NoJets);
Obviously, replace [YOUR ID] with your Blockland ID and maybe add more %f,%g,%h etc if it makes a minigame with about half the settings turned on.