The Mantis is a new UNSC bipedal weapons platform, fully equipped with a high caliber chain gun mounted on its right arm, multi-rocket system on its left arm, and UNSC’s energy shielding technology. The chain gun is effective up close, but has significant projectile spread and heat when laying on the trigger for long periods of time (once the chain gun overheats, it goes into a cool down sequence for a few seconds, disallowing the weapon to fire during that period). The rocket pod delivers massive direct impact damage, as well as moderate amounts of splash damage to infantry and armor. It has two firing modes, one being semi-automatic, and the second being a full volley of however many rockets are loaded in the pod. A total number of five rockets can be queued up by holding the weapon’s trigger down, or fired individually by latching the trigger. Once all five rockets are depleted, the Mantis initiates a reload sequence, replenishing the rockets after a few seconds.
The Mantis has two variants – Campaign and Multiplayer – which differ greatly in terms of damage, spread, and projectile speed. The Campaign version of the chain gun deals much more damage as it uses higher caliber rounds, and the rocket system is anti-aircraft.
Inspired by Halo Legends, the Mantis started out as an armored exoskeleton that Spartans would equip, augmenting their abilities. It had numerous weapons, roles, mechanics and shapes, and featured a dedicated shield. It also had the ability to jetpack, use thrusters, and fire a Railgun. We even had an early prototype that consisted of the Chief riding in a giant scaled-up Chief (Yo dawg, we herd you liek the Chief, so we put the Chief in your Chief so you can play as the Chief while you play as the Chief). The idea then evolved into an actual mechanized vehicle, which was more epic in scale and fit the UNSC better.
Once the concept was finalized and the Mantis was modeled and rigged for animation, we hooked up the bare systems to allow the weapons to fire and players to occupy the seat. During that time, there was massive animation work done to get all the parts moving and animating. It was difficult because there was nothing in the game engine that contained any logic for a mech. It was not easy iterating on values, because if we cranked the knobs on movement speeds or stomp delays, for example, the animation team would need to iterate on the animation content for the walk cycles and the stomp animation to compensate. Communication was crucial.
We ended up using a biped/vehicle hybrid, and there were significant amounts of content and code work done to bring this to life. After that phase came the heavy animation work and iteration process on the timings and numbers to get the legs feeling and behaving correctly in all the different possible situations across numerous maps. The team focused heavily on the Mantis’ legs and foot pinning to make sure the legs would behave when walking across various elevations and obstacles. Once we felt good with the timings and animations of the movement, we starting balancing health, weapons, and numerous amounts of other magical systems for Campaign and Multiplayer.
During the balancing phase, we discovered players were having a hard time knowing if the Mantis was reloading or not from certain distances, because the silhouette remained the same. To address that issue, we decided that it needed some sort of visual feedback to show when the weapons were temporarily down. It was definitely interesting and challenging to decide how we could animate the arms without it sorting into itself at different torso rotations and pitches, or looking like a Jersey Shore fist pump. Once we got the animations down, we found that it was extremely useful to players on foot, because it visually conveys the windows of opportunity infantry has when the Mantis weapon systems are down.
Overall, it’s slightly similar to the Scorpion tank in terms of health and armor, but it trades firepower for maneuverability, allowing the Mantis to be more agile than the Scorpion when needed. Also like the Scorpion, it is capable of being boarded by enemies and EMPed by a Plasma Pistol charge. One notable difference is that the Mantis is capable of using its weight to deliver a devastating stomp to crush enemies in front of it by pressing the melee button. Time your stomp carefully though, and remember that it’s a risk reward. If you miss and or use it carelessly, you leave yourself open to being boarded.
The biggest challenge when designing the Mantis was making it feel satisfying both for the players piloting it and players fighting against it. The goal was to have an awesome new vehicle in Campaign and Multiplayer, and not have it pulled off the Multiplayer boards because it’s impossible or too easy to counter. Through rigorous playtesting and prototyping, we pursued the “less is more” approach and simplified the Mantis into a much more focused experience.
One of the more effective roles for the Mantis in Multiplayer is base defense. It does especially well in close to medium ranges against both infantry and vehicles, but it’s good to have some cover just in case. You don’t want to be caught out in the middle of the battlefield in your big giant robot when the other team has a Spartan Laser. If used in an offensive operation (for example, escorting teammates toward the enemy flag), it is extremely critical to have a team supporting their fellow Mantis, killing potential boarders and anyone targeting the Mantis with a power weapon.
While piloting the Mantis is an enjoyable experience, so is blowing it up. Hooking up and polishing all the numerous little bits and doodads that splinter off the Mantis when each section starts taking damage and breaking apart was definitely the most fun (and time consuming) out of all the vehicles to setup. Each destruction asset piece is tuned to give proper visual response when popping off its parent region. There is a lot of attention to detail, and we made sure that the destruction is granular and satisfying.
Oh, one more thing to all you budding mech pilots: Watch your back, because she can be boarded from behind. And yes, that’s what I said.