10. The Portal Gun
blogcdn.comFirst-person puzzler Portal was the biggest surprise gaming hit of last decade. With its revolutionary portal system, clever narrative and wry sense of humour, the game turned out to be far more than just 'that puzzle game' that came with the Orange Box. The first Portal game was successful enough to warrant a proper sequel, which saw similar critical acclaim. Portal 2 also demonstrated further how the Portal Gun could be utilised as more of a weapon than just a navigation device, reinforcing rumours that the device might be working its way into Half-Life 3. This theory makes a great deal of sense, with Half-Life 2 also featuring an environment-manipulating device. The Portal universe has also been confirmed to be the same as that of the Half-Life series, so there's no insurmountable issues with regards to lore either. It would be a huge challenge to balance the Portal Gun properly outside of the 'testing' locations, but we can't think of a more exciting weapon to have at your disposal when clearing waves of Combine Soldiers.