First, a crucial clarification for search purposes: "Mini Militia 2015" does not refer to a different game, but rather the specific era and build of Doodle Army 2 that was most popular between late 2014 and the end of 2015. During this period, the app was still relatively lightweight (under 50 MB), hadn't yet been overrun by "Pro Pack" saturation, and featured a UI that is now considered retro.
If you played in 2015, you remember these specific mechanics vividly:
: A dedicated virtual joystick for movement on the left and an aiming/shooting stick on the right. Verticality