I feel like the Devils Lair was more of a "hold down the fort and be swarm. Oh look, you survive. Okay move on to the next area to be swarm." I do agree with you a tad bit on the arena type area because you are stuck in an area for a timing being, but it feels more like your interrupting a gang war and your just passing through and you got an asshole blocking your way, type scenario. If you think about, Every FPS is an arena. Your stuck in an area and the only way to move on is to kill everybody else. People don't think all FPS as an arena because we think of an arena as a small, enclosed space. What makes us think otherwise is the mission. In devils lair, your main purpose is to kill the leader, retrieved something, or even just get to the other side. During the video that was shown, one of the side objective is to repel all attackers until the traps are deactivated. If it makes you feel better, Play the arena in Darksider 2. Because that is a straight up Arena type battle. Where you kill certain amount of people in an open field and be awarded. While you got some "pretend" audience cheering in the bleachers.