Most of the games Pocket-lint saw at E3 2014 were playable, in that we had a chance to go hands-on ourselves to get a feel for the action. Unfortunately, not so Metal Gear Solid 5: The Phantom Pain.However, that doesn't detract from the fact that, on the evidence of seeing an in-game demonstration played by\u00a0one of the development team, it has every chance of being one of the best games of 2015.Like Metal Gear Solid 5: Ground Zeroes \u2013 the prequel to Phantom Pain \u2013 the next chapter has the rebooted, Kiefer Sutherland-voiced Solid Snake at its heart and an interactive game world that allows you to sneak, cover, run and gun, and drive any vehicle lying around.Unlike Ground Zeroes though, Phantom Pain's open world landscape is massive. We only saw a couple of segments in our demo, but we were told that the final game will be more than 200 times the prequel's size. There will be a lot of gameplay to be had and we distinctly get the feeling that, on the most part, you will be able to play missions the way you want, in any number of game styles.The first demo playthrough we witnessed had Snake and Ocelot riding on the back of horses to a location the hero had to infiltrate on his own in order to rescue a compatriot. This was done mainly using stealth by the development team member \u2013 specifically using sleep darts rather than bullets on guards.The main reason for this was to show the Mother Base aspect of the new game, in which stunned foes can be recruited to be on your side by knocking them out, tying weather balloons to them and sending them to your base in Fulton recovery mode.This is not the first Metal Gear Solid game that has offered this, so might seem familiar to fans, but to those in the audience who aren't used to dispatching enemies through the use of balloons, it reinforced something from the very start; Metal Gear Solid 5 is very much a game. Graphically it might be photo realistic in places, but this is MGS through and through, and that's gets us very excited.The Mother Base is a player's haven and, thanks to a leak by Hideo Kojima himself, we know that it will form the basis of the new Metal Gear multiplayer experience.Objects, people, even sheep can be sent to a player's Mother Base through the use of Fulton balloons in campaign mode. They will then help expand, customise and defend the base from attackers. And they, as Kojima revealed, will be other players.More on the multiplayer and Mother Base features will be revealed in due time, but from what we saw - running at 1080p in 60fps on a PlayStation 4 - the whole things looks truly stunning. And yes, a little mad too, but that's what we love about the franchise. We wouldn't have it any other way.Metal Gear Solid 5: The Phantom Pain will be available in 2015 for PS4, Xbox One, PS3 and Xbox 360.