In common terms, the flow of a map is describing how a map feels while navigating through it. Some cases which effect the flow are:
When a map has no flow, it means most of the times that it lacks some of the criteria which is listed in the next couple of aligns. Keep in mind that when you ignore some of the criteria, you may risk some serious flow issues on your map.
In common terms, gamemode entities are entities which are required for only certain gamemodes. Certain of those entities are:
Any other entities which affect the core gameplay are not considered as gamemode entities as the objective of the gamemode can be achieved without them or they can't be modified in the mapping process.
The base entity only appears activated in the modes Capture, Regen Capture and Hold (plus it's variants).