The $10 theory

[Grey Acumen]

I'm sure it isn't feasible due to copywrite, but I'd love to see a portal battle. You coudl have it set up so that you could place both end of the portal, and give yourself a shortcut to an advantageous area, but someone else could use their portals to place one end at a dangerous area and the other end they use to hijack one side of your portal, if you try to use your portal, instead of going to the area you wanted, you end up in the dangerous area.