When is it safe to turn around and shoot Hans while kiting?

When he stops to throw grenades (you hear a line about nerve gas or grenades). If you only hear his servos moving or his machine guns, keep running because that means a melee charge or gunfire.

Which classes work best for kiting Hans?

The guide is built around Medic and Gunslinger, because you need good ranged damage and good running speed. Medic also heals itself better. Other classes have a lower chance of success.

Is the guide still accurate?

Partly. The author notes that Hans was changed after the guide was written. Larger kite routes and keeping far away are now advised, with Gunslinger, whose headshots slow Hans by 30%, working best.

Tactics

KF2 Kiting Hans Volter as the Last Survivor (Medic, Gunslinger)

This guide explains how one player consistently beats Hans Volter when left as the last survivor, and it works for solo play too. It was written early and later partly outdated: the author notes that Hans received movement-speed and melee buffs, so larger kite routes are better now and movement speed and stumble power are the key stats. Medic, Zerker and Gunslinger can still solo him, but it is harder. For more Hans material see KF2 Hans Volter quick tips.

Updated note from the author

After Hans was changed, Gunslinger gave the best results: you can deal heavy damage from very far away, sprint backwards to keep distance, Magnums have high stumble power, and headshots slow Hans by 30%. Small kiting loops are less suitable; use larger ones and stay as far away as possible. If he gets too close, a double-barrel shotgun can jump you back while damaging and stumbling him.

Loadout

As a Medic, the author sells everything except the Medic Assault Rifle and Medic pistol for the boss wave and buys a SCAR as a backup in case he ends up alone or runs out of rifle ammo. The SCAR is easy to aim, has ample damage, good ammo capacity and long-range effectiveness thanks to its scope. A Gunslinger should take dual Desert Eagles and dual Magnums for damage and range.

Where to kite

Usually you are alone in phase 3 or 4 of the fight. The kite can take half an hour or more, depending on how much damage the team did first. Run around one fixed object so that Hans follows a predictable pattern. Two spots the author used:

Outpost kiting spot

Outpost: the building near your spawn in the middle of the map is small enough to loop quickly, yet large enough to keep a decent distance from Hans.

Catacombs kiting spot

Catacombs: run left (not down the tunnel), hug the right wall, return along the right path to where you started. Short but long enough to keep distance.

Shoot when you have good distance, ideally at a corner while he is at the previous corner, giving you a clear long shot.

When to shoot

Two sound cues rule the fight:

Servo sound (quiet, close): Hans is trying to melee you. Run, keep looping. Even if he hits you once or twice, keep moving; if you stop he will keep attacking, but if you keep running he gives up and goes back to grenades.
A line about gas or grenades: he stands still, so turn and shoot. Check which grenade: red explosive grenades deal huge damage so move soon; gas grenades are less threatening, especially for a Medic, so you can stay a little longer. Start running just before the explosive ones detonate or just after gas ones begin.

Your default state should be running. Only turn to shoot when you know he is using grenades, then run again. Look back often. If you cannot see him, he is about to round the last corner, which is a good moment to shoot. After a few laps you will notice he stops in the same places and can pre-emptively turn.

If he uses his dual machine guns, do not stop to shoot; keep running because stopping makes you vulnerable to the melee charge that follows.

Important considerations

Stay at full health. Heal at every opportunity; a Medic regains 6 armor each time it heals itself, so deliberately taking a little gas damage can be profitable.
Always know where Hans is.
After shooting during his grenade phase, run and then heal and reload at a safe distance.
If a charge is coming, equip any melee weapon (even the starting knife) and hold middle mouse to block. Blocking cuts damage but stops sprinting, so balance it with moving.
Doors help keep distance and appear to reduce his melee charges. None of the described routes include doors, but a Demolitionist reportedly kited him well using doors near the garage and trucks on Outpost.
Success rate for the author: 80 to 90% on Hard and 40 to 60% on Suicidal, where Hans can kill an unarmored player in two hits. It was not tried on Hell on Earth.

Summary

Buy a backup weapon for the last-survivor case, such as a SCAR for a Medic.
Use a small loop that is big enough to keep distance; both example spots work.
If he charges or uses machine guns, keep running; if he throws grenades, turn and shoot while watching which type.
Look back often, especially at the major corners of your route.

FAQ

When is it safe to turn around and shoot Hans while kiting?: When he stops to throw grenades (you hear a line about nerve gas or grenades). If you only hear his servos moving or his machine guns, keep running because that means a melee charge or gunfire.
Which classes work best for kiting Hans?: The guide is built around Medic and Gunslinger, because you need good ranged damage and good running speed. Medic also heals itself better. Other classes have a lower chance of success.
Is the guide still accurate?: Partly. The author notes that Hans was changed after the guide was written. Larger kite routes and keeping far away are now advised, with Gunslinger, whose headshots slow Hans by 30%, working best.