Choices

Was it intentional? I triggered all four wins.

Spoiler: My solutions

1. The easiest solution is to get to the win block in the centre of the other two on the roof.

Spoiler: How

Simply get B into the small housing on top of the other building and then push him with the free-draggable. You can push him hard as there is a nice tall structure to prevent him from flying too far.

2. The second easiest solution is to trigger the win block hidden from view at the start (i.e. it's on the back side).

Spoiler: How

B can walk over to the ball on the slider on the roof, knock it over and direct it to the win block.

3. The third easiest is to get to the win block nearest his spawn location.

Spoiler: How

After getting on the roof of the far building, B needs to come down the stairs on the edge, climb atop pillar-head R's head as he passes, then get off on the opposite side while being careful not to get zapped by the zapper bot, pass to the back side and walk towards the win block timing it in such a way as to get zapped as he is just about to stop before the win block. B will die and fall on the win.

4. The last win block by the lift is the only one that needs use of an exploit.

Spoiler: How

The only way to get a bot or ball to this win is to use the insidious Tripping on Air trick found by @vince in order to fall off the roof and then as he hits the ledge below, immediately tap the win. B will fall off the ledge due to his momentum, but because of the tap on the win, he will use the Autopilot exploit to climb back up on the ledge and to the win.