5. A Portal Crossover
Now I know I'm not the only one who is pining for this. You only have to search for 'Half Life 3 Portal crossover' to come across a slew of speculation, fanart, fiction and videos to know that this is something that can't be ignored. As creators of both Portal and Half Life, it's natural to assume there could be some link between the stories. Also, for those who don't remember, Episode Two ended with the Borealis, a ship from the Aperture Science institute, the same facility the Portal games take place in. There are also references to portal technology in Episode Two so the idea can easily be worked into Half Life 3. How would they crossover exactly? Who knows. The use of a portal gun? A bump-in with Chell, the equally silent protagonist from the puzzle game masterpiece? Perhaps GlaDOS will make a snide return. Would the melding of these two highly praised worlds be the ultimate conclusion, bringing both stories to a huge climax as Gordon fights tooth and nail using Aperture Science technology? Oooh I'm getting all tingly just thinking about the possibilities.