Greetings all,
My suggestion is to introduce level 5 in the next patch 8 or patch 9.
I am not sure on the numbers, but I am sure the number of participants has probably gone down gradually since the early release.
The more participants you have the better the testing and thus the better quality control.
I myself aloing with several of my friends have simply stopped playing this game, because every iteration I play makes the game less satisfying or more boring.
It is like the rule of satisfaction, the more you eat something or do something the less the enjoyment.
An example of this would be chocolate chip cookies or french fries. The more you eat them the less satifying they become as you eat one after another.
This was actually a topic discussed in a course during my commerce degree.
I offer this suggestion as a way to bring back players to test your game and maybe test 3rd level abilities, unless you feel you are getting a sufficient number of players for testing.
