X-Morph: Defense

If you do not have this by the time you’ve completed all main missions in co-op campaign, either replay some of the main missions or play some of the optional missions. If you did not play any of the optional missions in your co-op campaign, you may have a small grind. The Hawaii mission has a large number of flying enemies if you need to grind kills. I got this well before the final mission while playing all main and optional missions in co-op campaign.