Each challenge has a star value ranging from 1 – 3. To reach level 10, you will need to complete every challenge, which adds up to 101 stars. Three-star challenges are generally more difficult than one or two-star challenges. If you follow the technique mentioned in the roadmap, then these challenges should be nothing to worry about. Most of them are rather simple and straight forward, but I will mention a few that may need some clarification.
Hit 28-9+2: You will notice some challenges that are similar to this one. All you need to do is the math. That equation equals 21, so hit 21 on the dart board. There does not need to be a zombie on it.
Hit 1, 2, 3, 4, 5 in order: Challenges like this are best done in the first or second round. May take a few tries, because aiming is hard in this game, but it’s pretty simple.
Avoid trebles for two waves in a row: In darts, a treble (triple) is the thin red and green arc in the middle. Not the outer red and green arc where the zombies spawn, although they do spawn there in certain rounds. Just avoid killing zombies that are standing on the trebles. They usually pause there for a moment; so if you haven’t killed them already, just wait until they move off the treble to kill them.
Only hit doubles for one wave: Doubles are the red and green arc where the zombies usually spawn. Easiest done in the first wave, just kill the two zombies while they’re spawning.
Survive the third zombie stampede: Zombie stampedes occur every five waves, so wave five, 10, 15, etc. You’ll have to survive the third zombie stampede, this means reaching level 16. I got to level 16 several times before this challenge actually came up so don’t be too worried. Try to save your bombs for as long as possible, because level 15 can be quite hectic. I like to have at least one bomb to detonate at level 15, I’ve managed to make it there with two before, though.
Kill a total of 666 zombies: This will most likely be your last challenge to complete, simply because it comes up so late. I ended up completing all the challenges with 333 zombies left to be killed. You’ll be able to clear around 100 zombies a game if you can make it to level 15 each time, so it’s a very short grind.