The basic rules for Portals: Worlds Collide, as well as an update on the status of the project, have been posted to the Lead Adventure forum.
From their announcement:
I’ve decided to post-pone the release of Portals:Worlds Collide until in order to have more time to work on re-doing the miniature sculptures and work on the rules. The vast majority of the sculptures I’ve decided to entirely re-sculpt, as my sculpting skills have increased a great deal over the past few years (especially from when I started sculpting miniatures for Portals:Worlds Collide). Also, I’ve decided to change the scale to 28mm, in order to increase the amount of uses for the miniatures themselves (e.g. so that others can use them in other 28mm game systems as well as ‘Collide’).
On top of this, I’ve posted some of the Basic Rules (which is subject to change).