Commentary:

Cyan is not good at speaking in sentences. I try to just not have him do it, but here he is just using arrows, which seems really lazy to me. I don’t know if that’s really true, and the fact that he can’t really communicate more complicated ideas does sort of limit his interactions, so maybe I should experiment more with different ways to get him to have more narrative word balloons.

Anyway, he’s saying that the portal will continue to grow and destroy both their worlds if he does not continue to shoot it with the portal-shrinking-gun.