The phrase "oncoming wave" refers to a large group or force of something that is approaching or coming towards a person or a place. It often suggests a sudden increase or surge in activity or influence. Full definition
Apparently, the segment was taken from a few hours into the campaign where the players have to defend a structure from oncoming waves of zombies.I'm sure it would be fine to play through when taken in the context of the campaign, but all we got to see was the developers shooting zombies in the same small environment for too long. (gamecritics.com)
Outback — The outback is the terminology given for the area of the sea where surfers sit and wait to catch oncoming waves from behind the impact zone. (cornishwave.com)
Charlos gives the back of my board a push into a small oncoming wave. (health.com)