This mission is so titanically gargantuan that we've gotta split it into two pages. As such an enormous level, it's home to quite a few interesting sights and gameplay options. First, no ice. You're closing in on an intense heat signature and are surrounded by volcanic caverns and scorching temps. You also see a new Akrid here, one that behaves quite like a scorpion. Finally, you'll get to pilot a new transforming VS - the spider-legged tank you just blasted through at the end of the last mission.
So, let's get started. Right away you've got a truckload of flying Akrid. Zap their hives and zipline over the wall to meet the scorpion Akrid. A well-placed rocket blast to the tail should cleave it right off. Head up top to the data post and look north for a rocky path that leads back out of this room. It'll take you to the "V" target mark - it's about eye level with those three Akrid hives you just popped.
Next on the path is a two-story site that holds machine gun ammo up top and a ton of bugs down low. Either way, up or down, you should clear the room before breaking the shuttered door. Once the area's quiet, trash the door, activate the data post and take a look ahead. It's a ramp packed with Akrid. They're just standing there. For whatever reason, they won't make a move until you do. So, toss a grenade down there to stir 'em up, finish off any rockets you might have left and, once the ramp is clear, head back into the room where the hive was and grab the shotgun.
Back at the end of the ramp, there are two ways to go. Ignore the left and focus on the right. You'll see a hive on the wall, a crapload of bugs and a few larger Akrid roaming around, itching for a tasty human snack. Kill 'em all. Then, head to the southwest-ish door for a VS. Be sure to grab the VS rocket launcher before heading back in the gate, which just happens to take you back into the room you were just in. Grab the "O" token along the eastern wall below, nab some extra shotgun ammo, then pilot your VS into the main chamber where another scorpion Akrid awaits. Off it, hop in your new transforming tank VS and head outside.
The lava-drenched path ahead is best navigated by this VS' tank mode. The spider form may look cool, but it's just not practical or fast enough for this leg of the mission (it can also plow through many bugs at once, saving a ton of ammo in the process). Blast a path ahead until you come to a room swarming with flying Akrid. Straight ahead, to the south, is the "L" token. It's floating on top of a small ledge above the energy container (it's best to secure the room, zip up there and tag it in person). Now take the VS outside, activate the data post and get ready for another intricate battlefield.
There are several paths to take here. They all lead to the same place, but your experience will vary depending on which Akrid you attract, how much T-ENG you have at this point and which guns you're still using. The main attractions down here, however, are the "C" token atop a VS hangar to the west, another tank VS for emergency use should your current one crap out, and another top-of-the-line VS in cliffside hangar across the lava lake. Regardless of which VS you use to spank around these bugs, they all go down the same. The tank works quite well with is cannon and laser turret, so try to keep it around. Once you need to get up on the broken highway, however, it's time to switch. Any of the smaller ones will do - even the high-tech one on top of the ledges. Pick one and head to the exit door, located on the southern end of the highway. Considering the lengthy VS usage of the level, be sure to activate the other two posts in this area - one is to the northeast and the other is just before the exit.