Pretty cool but there are a few games specifically made for this sort of thing. Seems like puzzles would be pretty simple as the ball though unless you had to use a bounce system that wasn't going to set itself up because you pressed a button.
In all the idea seems too static, there is no complex way of achieving your objective. The portals in the game itself made it more dynamic but as the ball i doubt you could effectively use the portal gun without setting it up using buttons and triggers in hammer which would then make it static again.
Perhaps as a side goal in a puzzle, normal first person play through a puzzle and a small ball puzzle would be part of it, getting the ball onto a button at the end to activate something for the first person play, perhaps even swapping in and out of the ball to make portals so the ball can continue. If any of that made sense...I tend to ramble and describe things poorly.
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