I would've loved it if this Underground DLC and future expansions included at least a couple of missions that continue the plot of the game. I think the best part of the game was the road to level 30 not only because gameplay was more fun and rewarding, but because of the story and narrative. It was an engaging experience to find out what happened to the First Wave, uncovering the mystery of the green virus, and knowing that there's still one person out there with a bioweapon that can wipe out the entire human species. Instead of always adding content that requires us to grind repeatedly with unsatisfying results most of the time, add some story missions here and there that can allow players to sit back and enjoy without having to worry about what they receive as rewards