This guide will be in the following order:
Section 1: What you should know that is not explained
Section 2: Tips and tricks
Closing Notes

-When characters die, they are lost for good.

-Death of the main character will instantly end the match. Your main character will not be lost and any characters that were still alive when the main character dies will also not be lost.

-Your army member limit (including the main character) is 8. If you complete a level with 8 members remaining, you will not recieve the characters you would normally recieve from the level. It is best to keep your party at 6 or 7 members by selling members for skill points.

-during battle, the top right arrow pointing at an open door icon will allow you to exit a match at any time. You will never recieve any credit for a match in which all enemies are not defeated and leaving a match this way will NOT bring back any allies that died during the match. This function is only useful if you have to quit the game immediately or you have reason to believe a unit will die and want to grind earlier levels before continuing with the current level.

-The army menu on the world map can be used to both sell units for skill points, or skill points can be used to upgrade a character's (but not the main character's) stats. This appears to be possible about 3 times per character.

-Unit placement in levels is always completely random.

-Sometimes there is a space within your movement range that you can't move to no matter how many times you click. This is because of other unit in the way causing you to walk aroud them. Though it appears you can move there, it is probablly just 1 space out of your range because of unit positioning. If this is occuring n the first turn, try moving another unit before moving the one your trying to move now. maybe your trying to move a unit that is boxed in.

-the skill tree has many branching paths and you may find it hard to remember if you purchased the last skill in a particular path of the tree, but in this case you should look at the border of the skill. Skills you have purchased will have a yellow border.

-If you look at the skill tree very closely, you will notice that there is a point where all previous branches end and some new branches start. The first skill in each of these new branches do not require you to know skills from the old branches, so you can start learning these skills at any time, even before the previous branches.

-Moving all units towards the enemy on the first turn (using both of their moves if they have 2), then passing your second turn to wait for the enemy to come to you is usually a wise strategy. It usually allows you to use all of your skill points to attack, allowing you to take less damage and lose less units.

-You will likely rack up multiple copies of each specific unit. Maxing out 1 copy of some of the units may be wise, but don't overdo it. Remember that using skill points for your main character's skill tree is a big priority.

-be sure to use both short range and projectile units. Though the main character is pretty tanky and can take a beating, having a few more close range targets to take hits is helpful, then have your ranged units attack from behind. Just keep in mind that many ranged units only have 1 move per turn, not 2. So place them very closely behing your close combat units.

-Having trouble with a level? More allies could help, or you could examine your skill tree. The skill tree gives your main character stat increases, but it also has active skills that he can learn such as healing. Don't underestimate these skill options (sorry that the skill tree is not covered in this guide, but it is fairly straightforward in my opinion).

-enemy A.I. is fairly basic in this game so keep in mind that the unit closest to the enemy is always more likely to take damage. This should usually be the main character since he is so tanky, but you should also know when to withdraw him and have other units take the hits.

- If a skill has a blood drop icon on it during battle, it costs HP to cast. These skills may provide important advantages such as being the only way to attack multiple targets in the game, or ways to summon more units mid battle, but they take away an entire 30% of your health. USE CAUTIOUSLY. They usually are not a good idea if the unit casting them is in front, taking damage.

I hope these tips and clarifications are helpful. I originally planned to do level by level walkthrough but it remains incomplete enough that I decided to completely scrap it and just publish what I have. Hope what is here is helpful to new players. <3