A pier is doused with gas and explodes with all the bad guys on it. This was shot multiple times. First, stuntmen do various partial burns and hand ratchets send them flying off pier while fire is all around them. Next is a wide shot of the entire pier blowing up with no stuntmen on the pier. No CGI was used.
Sylvester Stallone and his friends fight a group of 15 bad guys in underground tunnels using various MMA moves, submission holds, knife techniques, gun fire and breakaway props.