After you beat chapter 2, you will unlock the trials. The trials allow you to replay a chapter that you have already beaten, but with extra things working against you. Enemies will have new paths or be harder to beat, for example, or the stage will be shrouded in darkness.
There are three different versions of each chapter that you can play in the trails. Just like in the originals, all that you have to do is win in order to get the prize, but you only get a prize the first time you win each leg of the trail. The trails are a good way to earn various prizes such as large quantities of gyms for free, as well as evolution cheese.
Evolution keys are used to unlock the evolutions on the right side of the evolution menu, with the standard left side evolutions being unlocked simply by having a high enough experience level and by paying coins. The Chi evolutions provide a different sort of boost in each level, for example, the ability to pick one skill right at the beginning or to swap a skill out right before facing the final boss of the chapter.
After passing chapter 2, you’re going to find different and more unique variations in how each chapter is played. For example, in chapter 3, the size of the level is extremely small, and a new boss character will show up every two minutes instead of every five minutes. That means that this level is eight minutes long, rather than 15.
How many chapters are there in this game at the current moment? As of the writing of this article, there are 35 total chapters. That means that you will have a lot of challenges over the course of playing this game, as well as an absolutely massive amount of zombies and bosses to face. You will certainly have lots and lots of excellent equipment that you will be able to find, as well.
After you max out the upgrade level of one of your orange skills, as you know, you will be able to evolve it into a brand new skill. The prerequisite for most of these evolutions is to upgrade the green skill that matches your orange one. You only have to upgrade that specific green scale one time before you become eligible to evolve the orange skill, though; further upgrades to that green skill will not help at all.
The exception to this is upgrading the drones. In order to evolve the drones, you have to have both of them on your skill list. Upgrade both of them to five stars, then they will be able to evolve into the “destroyer“.
After you evolve them, you will have a free skill slot that you can then add another skill to, which can be a massive boost as you are getting closer to the end of a level. This is the only set of orange skills that Will lead to a free slot after evolution.
Not only that, but the drones are one of the best orange skills that you can have on any stage, because the sheer number of missiles that they unleash can lead to a massive amount of damage to big boss characters. Even though they are not auto targeting, they also aren’t very difficult to aim.