Talk to the Commando and Meet the Commando at city are missions in Ratchet & Clank. A distress message found in an infobot led Clank to, futilely, try and convince Ratchet to help the Commando fend off against the blarg. Ratchet initially refused, desiring instead to find Qwark after they were betrayed by him, but needed Clank's robotic ignition system to fly Qwark's tour shuttle. Clank extorted Ratchet into traveling to planet Batalia to help the Commando.
Upon arrival, instantly talking to the Commando and thus completing the "Talk to the Commando" mission, they were ordered to head to the walled city and meet him at the entrance. Ratchet again stated his reluctance to selflessly help him, at which Clank called him a coward.
The Devastator will be available at the Gadgetron vendor. A rocket launcher costing 10,000 bolts, it has excellent range and damage, and is one of the most useful weapons available. A small swarm of scoutbots patrol the area up ahead. They will fly down and try to zap you, but are otherwise not notable. Two blarg paratroopers guard the route forwards. These robots will side-flip, much like Ratchet, and then fire a rapid stream of micro rockets at a low angle, traveling upwards. Since they cannot redirect once firing, you can simply side-flip to dodge their fire and destroy them. An aircraft will bomb a platform behind them upon approach, leaving only a thin path for you to cross.
Note that to the right is a stack of crates that hide a cave entrance with some ammunition. Since a nearby bridge remains closed, you should continue right, fighting another paratrooper, and head to the area below. Some scoutbots roam here, but the real threat is the presence of camouflaged blarg bombthrowers. These units hide underground and within a type of plant native to this planet, popping up only when you are within range of their throwable bombs, then quickly fleeing and hiding elsewhere. Stay vigilant and prepare to dodge them at any time and simultaneously return fire, unless the cycle continues. Once cleared, turn the bolt crank to extend the bridge.
A cannonball tank will start driving across the bridge. Well-armored and packing a rapid-fire bomb-throwing cannon with medium range, it is a solid threat, but is easily defeated with the Devastator nonetheless. Head across the bridge, then turn left and head down the slide of water, but watch out for the two paratroopers at the bottom that will immediately open fire. Behind them is a large area with another lone tank guarding two bolt cranks, and a number of blarg bombthrowers hidden within the vegetation. The Glove of Doom can prove useful here, and after turning both bolt cranks and defeating any enemies, you can safely travel across the second bridge and meet the Commando.