19. Call of Duty 4: Modern Warfare (PC, also on PS3 & 360 and Wii as CoD4: MW Reflex)

As a fan of Call of Duty from the very beginning, this game was the pinnacle of the series for me and showed off everything the franchise can be. Moving the time period from the over-done world war II setting to the modern day (meaning some very cool weaponry and varied gameplay) yet still retaining everything that made Call of Duty 1 & 2 great; a glorious single player campaign combined with a superb multiplayer.  

The single-player campaign, whilst relatively short, is perhaps one of the most memorable and shocking. A solid narrative pushed you along, but added some truly shocking moments not seen in video games that made full use of the first-person perspective (nuke anyone?). The multiplayer in Call of Duty has always been good, and CoD4 was no different. New weaponry and a levelling system added to solid CoD gameplay.

Clue to 18: The PC version of this game created huge controversy because of a mod

San Andreas?

Oh my god.

Awesome. I didn't think this game would be guessed. It's not very well known I believe. I just checked, apparently it only sold 70k.

So, yes, correct. Kula World, or Rollaway in the US, it is!

You're being too literal. The word "chain" is not in the title.

The Legend of Zelda: Ocarina of Time

Yes! A bit too easy, I'll have to think of better clues!

Getting very warm, but what if I told you the word "time" is also not in the title?

Think about what my clue means and think of a game similar to Ocarina of Time.

Crosses put together can look like a chain so... Chrono Cross?

#19 - Kula World is unlikely to be a game known by many here. It is however, an utter genius puzzle game. Actually, it looks kind of silly. The player is a ball, literally. Mostly a beach-ball even, that rolls around picking up pieces of fruit and keys. The catch is, that the ball can roll around the stages in all directions that are made up out of a couple of beam-like (beam as in, construction) platform things. The player must find his way (literally) around these beams and grab the keys to the goal. This is done by rolling around them in the 3D space at certain points or jumping from one beam to the other. It is fact quite complicated to explain, because some later become extremely complicated themselves. But the best way to describe the game's uniqueness; This is the only game for which I've ever bought the digital re-release!

#18 - ?
Best. E3. Ever.