Hello,

Although Ed Boon and other members of the MK team have often stated that the games have been based on kung fu films they have seen, they never really elaborated on which films these exactly were. I've decided to compile a short list of many similarities between certain characters and martial arts films. Note this is not a complete list, but rather a collection of similarities I have come across in my own personal experience.

Scorpion: The classic Shaw Brothers film Five Deadly Venoms featured a character known as "The Scorpion". However, these characters feature no other similarities. Very rarely, the darts attached to ropes are used in films in a manner similar to Scorpion's spear, such as in this video at about the 2:32 mark:
http://www.youtube.com/watch?v=a32xXAJA9iM

Johnny Cage: I'm sure you're all aware of the Bloodsport references with this guy, so I don't need to elaborate on those. Johnny's "shadow" moves, more specifically his shadow kick, may be inspired by the No-Shadow Kick, sometimes known as the Shadowless Kick. In Chinese culture, with something is called Shadowless, it means that it is "so fast it does not leave a shadow". As such, the No Shadow Kick is depicted as incredibly fast. The nut punch is also a recurring theme in kung fu films, often used as a way of defeating an otherwise invincible foe, as seen in this video at the 6:25 mark:
http://www.youtube.com/watch?v=kxjrxIGnvVk

Liu Kang: Although one can easily find the similarities between Bruce Lee, Liu Kang may also take inspiration from the actor Gordon Liu, and his character Liu Yu De in the film "36th Chamber of Shaolin". Liu Kang's famous Bicycle Kick may be a combination of techniques, including the kick seen here:
http://www.youtube.com/watch?v=SMPtpcmVfxE
and seen in this video at about 1:15:
http://www.youtube.com/watch?v=nom4tJ4zmUg

Noob Saibot: The theme of warriors dying and returning as demons has been in a few films, most notably the Shaw Borthers flick "the Nine Demons". (However, this film is utterly terrible and I do not reccomend it.)

Shang Tsung: A reference to Lo Pan in Big Trouble In Little China. However, Shang's old form is shown having long hair and a beard, as are many, many, MANY kung fu villians:
http://www.youtube.com/watch?v=oXcdAtL8yNM
Shang Tsung's attack on the Shaolin Temple with a group of Tarkatans may be a nod to the true-life martial artist Pai Mei leading a group of Manchus on an attack against the Shaolin Temple, which was subsequently burned. The Manchus are sometimes known as the Tartars.

Raiden: Obviously a reference to Thunder from Big Trouble in Little China.

Kenshi: The fact that Kenshi is blind yet still able to fight well may be a reference to the film "Crippled Avengers", in which a character is blind but still able to fight. The nack story of Kenshi wandering Japan to fight powerful samurai is likely a nod to the real life swordsman Miyamoto Musashi, famous for his Book Of Five Rings. Musashi is known to have never lost a duel.

Jax: Jax losing his arms and replacing them with metal ones may be another reference to "Crippled Avengers", as the villian's son has his arms cut off below the elbow and has the replaced with metal ones. In the film however, these arms have varied functionality, as they are retractable, and are capable of firing darts. Bo Rai Cho: Bo Rai Cho is likely based off of the real-life but often heavily fictionalized man So Hua Chi (sometimes known as So Hi, Beggaer So, or Sam Seed). So is often depicted as a drunk beggar who uses a powerful martial arts fighting style that utilizes his drunkeness. He was most famously depicted in the film "Drunken Master".

As stated above, this is not a full list, but rather what I have found in my experience with films and the Mortal Kombat series. Comments are appreciated.