Successfully complete a campaign, then save after the credits finish to have the option to replay any mission in that campaign with your previous stats.
Play as Cirith:
Successfully complete Walter or Leinhart's campaign to unlock Cirith.
Play as Morene:
Successfully complete Rupert or Cirith's campaign to unlock Morene.
Play as Rupert:
Successfully complete Ellen's campaign to unlock Rupert.
Play as Urukubarr:
Successfully complete Morene's campaign to unlock Urukubarr.
Better Leader Equipment:
Since a leader's skills all contribute to his or her level now, the leader's equipment stays on even if a troop changes jobs. Equipment available for a leader is often determined by the melee skill. The higher the melee proficiency, the better the bonuses for that equipment.
You can trick the shop into generating better items, you can temporarily create an infantry unit of a level equal to the unit you want.
For example, you have a melee 10, range 20 longbow unit. Reset the unit to a level 30 infantry unit and start shopping. Once you find and buy the weapons you want for a particular leader, reset the unit back to its original job (in this case, the longbowmen). Your leader may now re-equip the gear.
If you have an excess of gold but need experience points desperately, you can hire high level mercenaries in the Pub and simply reset their units and re-allocate experience to your core units. Like equipment, you may also save and load the game to randomise the mercenaries until you get the ones you want. Note: This process is irreversible since the mercenary is permanently added to your force roster.
Carry Over Skills And Equipment:
After clearing a campaign, an option to save your game will appear. This save allows your leader to replay select stages in his/her campaign with your last configuration of skills, equipment, and units. Enemies don't get stronger, and you may continue training and upgrading your units after each mission.
Since KUFH gauges experience differently (the game determines the cost of a skill increase on the sum total skill levels instead of a particular skill), you will want to keep all the skills of one leader or officer within one level of each other to avoid paying an exorbiant cost of increasing a skill. For example, if you have a leader with a melee of 9 and a range of 1, your cost of increasing the range skill from one to two will be the same as increasing your range skill from nine to ten. By increasing your skills equally, you will be able to economise on the skill points you spend.
However, this doesn't help since you want each unit to be good at its intended job. Therefore, you need to identify each unit's primary skill. For example, an archer or longbow unit will have range as its primary skill, even though melee and range are required for the unit. The reason for this choice is because an archer unit is useless unless it is firing. The range skill needs to be high for this unit or it will not be very helpful. As a principle, be sure to have a unit's prime skill as three to four times the amount of its melee skill (which is used for all units).
If you are forced to choose between increasing a unit's primary skill or its melee skill, opt for the primary skill once the melee skill is sufficient to allow the unit to survive brief contact with enemies of equal or slightly greater melee skill. Usually, a melee skill of 5 or 6 is enough in KUFH (as opposed to melee 10 in The Crusaders). For the most part, your core infantry needs to be around to screen your non-infantry units from harm. That's what they're being paid for anyway.
Unit Name - Prime Skill(s)
Archers and Longbowmen - Range
Cavalry and Riders - Frontal and Riding to 8 or 9
Infantry and Knights - Melee
Mortars - Gunpowder (2 times Range) and Range
Officers in your core unit - Magic skill to 25 or skill officer uses most
Spear and Axemen - Melee (1.5 times Frontal) and Frontal
Sappers - Teamwork (2 times Melee) and Melee
Scorpions, Mammoth, Dirigibles - Taming. Melee (1/2 of Taming) for Scorpions