Portal should be a cgi movie, i think it would work better with the humour....i may be wrong. Half life film would suck, the setting and atmosphere would be awesome but the aliens (head crabs) are to hilarious to put on team, what they gonna do? Order 50 turkeys, stick them on stuntmans head and send them to the movie set. lol
JJ is only on this because of Star Wars, if he makes that movie early then these movies may happen. But i doubt they will, not by him anyway. Neil Blomkapm (District 9) would be far better director for Halflife. An Valve could make there own CGI movie for portal....they make cgi cutscences etc in their games so should just invest in that.