I made another video on this, but I had a couple questions for the update. It would be great if you could answer them. I might end up making a series on this game.
Great video! https://youtu.be/jHrjX4QTeR0?t=946 was a good moment to use a stun grenade though :) Be careful with the cover indicator too! It turns yellow if your unit is flanked! Flanked units are easier to hit! You should always try to flank your opponents before shooting at them, but be careful - if you can't kill them right away you might eat a lot of damage! It looks indeed like you are playing an older version of the game, try downloading the new one! The tank has only a 50% chance of appearing at the start of the forest though :) I'm currently working on tank battles which should make tanks REALLY fun :)
You just have to pay once for the game! I think this page summarizes it pretty well: https://itch.io/docs/buying/already-bought
You can additionally request a free Steam key from me as soon as the Steam version is available!