From certain levels, there will be sub-levels for some of the main building upgrades, in order to ease off the burden of collecting and maintaining large amounts of resources.

For example, a Lv. 25 Command Center will level up from 25 to 25.1, then to  26.

■ Sub-levels apply to the following buildings.

[Sub-levels from Lv.25]

- Command Center

[Sub-levels from 26]

- Anti-Tank Bunker

[Sub-levels from 27]

- Barracks

- Hangar

- Command Tank CP

- Resource Depot

- Embassy

- Recruitment Center

- Heavy Tank, Main Tank, Artillery Factories

- Heavy Tank, Main Tank, Artillery Depots