Glitches?

• You can apparently get Munio's gear early by defeating an enemy in a certain battle in Ononhaar and picking up the chest he drops. This takes a long time and a lot of luck to get the opportunity, so it might not be practical in a speedrun despite being very useful once acquired.
• I've heard that you can recruit temporary units permanently by hiring them when you don't have enough money. This could be used to acquire Dervishes, Amazons, and other units early in the game when they would normally only let you temporarily recruit them.
• Undead Legionnaires and Undead Summoners have the innate ability Fleshless Target, which greatly reduces damage caused by ranged attacks. Occasionally though, this doesn't work for whatever reason. This means Archers and Gungnirs/Peltasts can sometimes do heavy damage against them, making them not completely useless in battles against the undead.