16. Metal Gear Solid (PS1, also on PSN and GC & X-box as MGS: Twin Snakes)

Back in the late 90s, everyone was talking about this game. The story, the stealth mechanics, the guards throwing grenades down vent shafts, the boss fights! I however, didn't know what the fuss was about and ignored it... until I played the demo. I then went out and bought it the next day.

So much about this game felt fresh and innovative. For the time, the stealth mechanics were amazing; constantly hiding behind cover, ensuring you didn't leave footprints in the snow; using camera blind-spots. It was all new. The level design was also superb using the keycards to gain specific access to new areas but still immersing you into the idea that this was a top secret facility that you were infiltrating. Even backtracking was fun!

It also had the unique Kojima style that rewarded clever and original thinking. The fight with Psycho Mantis is a clear example of this (switching controller input around and him reading you memory card!). Most games and designers wouldn't dare breach the fourth-wall for fear it would destroy immersion, yet in MGS it they breach the fourth wall on numerous occasions yet it actually improves immersion into the game world. Other examples of rewarding original thinking by the player include having the wolves piss on a cardboard box thereby enabling you to traverse their territory without getting attacked or using cigarette smoke to ID potential laser traps.

I haven't even mentioned the story which is probably the best in the series. It made you feel like you were truly in a movie and was a superb cinematic experience with a rollercoaster of emotions. It also had two seperate endings which always helps with the replay value and didn't go too outlandish as happened in MGS2.

Unfortunately, it hasn't aged well, so with my new scoring system it's dropped 9 places from last year!

15. Uncharted 2: Among Thieves (PS3)

The original was good, but didn't make it onto my list. The sequel on the other hand took everything that made the original good, subtracted the crap and added an extra layer of awesome! Everything in this game just clicked and it acheived everything I want from a story-driven third-person action adventure game. It combined the platforming and puzzles elements of Tomb Raider with the shooting and cover system of Gears but also added a more strategic stealth element to the game rather than relying on the constant spawning of enemies in the original. Not particularly original you might say, but extremely ambitious and very difficult to pull off with the amount of polish they acheived. 

I haven't even mentioned the amazing set-pieces that are quite simply mind-blowing. Gun-fights in a collapsing building, platforming on bombarded debris and an amazing combination of platforming and shooting for the train section. These were all aided with some clever physics, amazing visuals and some of the most beautiful vistas I've ever seen in video games. The views on the mountains and at the top of the hotel are truly amazing. The co-op and multiplayer are also good fun and work very well, although the single-player is really what makes it for me.

Strangely, no other Uncharted game makes my Top 50. Uncharted 2 is where I felt they got the balance, story and polish just right. Lastly, it's set in Nepal for a large portion of the game, and as I'm Nepali by descent, it holds a special place in my heart

14. Star Wars: Knights of the Old Republic (PC, also on X-box)

Bioware make great RPGs. Mix Bioware and Star Wars and you get the greatest Star Wars game ever created. The game was pretty much an entire Star Wars trilogy wrapped into a single game and even with its own lil' "I am your Father" shock moment. The story was superb, the characters were deep and interesting but still quintessentially Star Wars. The relationship between you and the other characters was still player influenced as with older WRPGs, but were given a new level of polish due to the focus on story and the new graphical hardware available.

Being set 5000 years before the original Star Wars trilogy helped by giving the game greater freedom in comparison to other Star Wars games; not trapped by the original storyline but still balanced within the epic Star Wars universe with lightsabers, force powers and space battles. The sequel didn't make my list, but is also a great game if unfortunately a little rushed. 

Go Scoobes go!

13. Half-Life + HL: Source + Black Mesa mod (PC also on PS2)

I think this game really needs to be put into perspective to truly appreciate the revolution it brough to the FPS genre and general single-player storytelling in video games. It came out in a time where FPS' were all arcade shooters like Quake, Doom or Unreal, had little to no narrative, poor AI, unrealistic damage models (didn't matter where you hit someone, the damage was the same) and where everyone was a beefed up generic soldier (actually, not much has changed in that respect). Half-Life broke the mold. You played a geeky scientist; headshots would actually kill; the AI actually flanked you and would flush you out with grenades rather than running into walls; and the narrative was excellent whilst immersively presented throughout the game world. 

Quite simply, it was the first game to truly combine all these aspects into one revolutionary package. The narrative especially; for the first level you didn't even get a gun as it just built-up tension and set the scene for the rest of the game. The lack of cut-scenes and the fact that everything was seen in first-person also meant that a greater level of immersion could be maintained making you actually feel like you were Gordon Freeman. It also balanced the action with superb level design and puzzle elements requiring you to actually use a modicum of thought as opposed to the pure gibb-fest of previous FPS titles.

It's also worth remembering that the mods that sprung from this game (namely Counterstrike, but others like Day of Defeat as well) have gone on to become some of the greatest and most popular multiplayer FPS' in the world, many still being played today. Basically, nearly every FPS on the market today has been influenced in one way or another by Half-Life.

Wolfenstein 3D? or Doom?

Clue for #12:

The first game of a now-defunct developer who were well known for their PC games but whose last title was an Xbox 360 game.

Right platform.

Now the metagame that my game started is more popular than the genre the original game is in.

It also made Tower Defense type games really popular.

Catchup time.

16: Where the main character’s arc really should have ended. Games in this series are always released in the same month, for a very specific reason.

15: With a greater variety of weapons and environments, a beautiful soundtrack, an improved cast, and a surprisingly excellent multiplayer segment, this game is considered one of the best sequels of recent years.

14: This studio has not had a misstep for a very long time, and this game showed once again their extraordinary range, by demonstrating that they can make a serious game just as well as a humorous one (indeed, better).

13: This game’s predecessor was loved by all initially but eventually left a sour taste in people’s mouths. This game was just as well loved as release, and still seems to be very well loved.  

Sounds like you're talking about RTS as the genre in which case it'd be Dune II.

But I don't remember anything Tower Defence related so I suspect it's an RTS that had Tower Defence maps like Starcraft or Age of Empires II?