Another not so useful tips

1. Don't bother using S-bullet during mission, used it only for promoting your units.
2. Picking a tactical weapon for the mission will give you extra damage output but it may not be the best options, just stick to your favourite weapon.
3. Rescruing might sometimes let you recruit a high rank character so it is best to keep a slot open just in case.
4. Promote your favourite high rank character to 3*star will makes the mission significant easier. They give extra health so that in event of getting hit during mission that can save you some frustrations.
5. Every 25 character level will give a team stat boost, so .level up character directly to every 25 level and possibly equally.
6. Danger zone give you double the resource but have higher enemy count and is more risky.
7. Exile the weakest member to save up your food/water consumptions, exile member will give badge and refund all the resource you spend except S-bullet.
8. As much as you hate the advertisement, sometimes they give nice rewards (S-bullet, bottle caps, gas), you can spend the ads token to buy VIP item.
9. It is absolutely okay to lose (game over), in return you will be given a tons of material to start over on certain days, it just affect how far you survive and food/water will be refilled to full.
10. Pray to the RNG god

#10 is a little dubious, but thanks :)