10. Half Life
The thing that would make this movie boring as hell or seriously wrong and wonky is the protagonist. Gordon Freeman is one of those 'blank slate, let the player feel like it's them' type of characters that would have to be expanded to be at all interesting on screen. Also, the majority of the game is spent in a long attempt to get out of an underground facility. If you trim out those scenes to focus on the plot intensive ones you lose one of the essential elements of the the half life experience. Unfortunately, you'd kinda have to do that if you didn't want to lose a truck load of money every day as people walk away from a boring flick. The best way to do a Half Life movie would be to crunch the plot of the first game into about half of your screen time and then have the rest of it be based on Half Life 2. That's really what gets all the praise for Valve when you think about it. Despite how well you might wanna remember it, Half Life was just another FPS game. The sequel is the one that had a story good enough to be worthy of consideration. That story would make a great movie, but there's a big pit fall. Brainy, slow paced sci-fi that's ambiguous is as already something that Hollywood avoids when the budget gets too big. Like Mass Effect, Half Life wold need a huge budget to work. Valve is a smart enough company to not fall into the trap of letting a studio ruin their property, but that leaves us with one option to get a great Half Life movie into theaters. That would be Valve taking the UMP (Ubisoft Motion Pictures) route and making it themselves. I am by the way, totally fine with that...
after we get another Half Life game! Seriously Valve, no movie dessert until your finish your dinner plate of a game (which given the amount of time it's been since episode 2 should now hopefully be a feast) and let us eat or electric veggies.