it's really a fun game, I wish it has more progression,events, cutscenes, it looks really promising, I really enjoy the gameplay, although some things are lost in translation, especially the skills which is kinda game-breaking.
also the shop rng isn't really friendly imo.
for those of you that struggles to complete whatever, here's a quick solution for all your problems:
1. use all warriors, aim for 5 warriors and 3 orcs combos (warriors for lifesteal, orcs for attack speed)
2. use 2 Sanas (orange orc warrior), as Sana's dmg heal herself and others if her own hp is full
3. 2 Sanas is very important, the others are just meat shield, they all meant to die.
4. position those 2 Sanas at 3rd row so the enemies will be within her reach at the start, and the others at the back
5. use 2 Alvas (elf warrior, optional) since she can teleport, she's weak, easy to die and will deal some dmg when she does, and when a warrior die, the others will get lifesteal
6. the idea here is that other warriors have to walk unlike Alva, so when the Alvas dies, and the other melee warriors finally engaged with the enemies, they come packing, and Alva deals dmg when she dies.
7. and when the other warriors dies and you're left with 2 Sanas, watch all hells breaks loose. those Sanas are mad, they heal themself and each others
8. if you're unlucky and your Sanas dies before the others, you're still gonna get some really really nice resistance when you're down to 2 warriors
9. seriously this combo is the best combo imo, and doesn't really need skill to support, so you can utilize those skill slots for more money skills after the essentials, and it's the easiest simplest way to get "true ending" if the shop rng is good
10. congratulation, you broke the game, now go get bored in endless mode, good luck