Basic Stage is a holosseum stage in all the titles that is very, well, basic. It features regularly-shaped walls, identical corners, and crates in the middle. Though very simple, it is the ideal battlefield for many robos.
The brown wooden blocks can be destroyed by gunfire. If your set functions better in a clearer arena, focus on destroying them.
If your set relies on cover, try to stay away from them as much as possible, to keep fom drawing attention towards them.
If destroyed, they will not appear again during that battle.