So here we go;
In 1849 the first "computer" was created called The Difference Engine by Charles Babbage. I say computer but it was defiantly not what we are used to today, The Difference Engines was used as a calculator, but not for normal mathematical arithmetic, it was used to calculate polynomial functions. But The Difference Engine was never produced.

The next important creation in this history would be Colossus, a computer created by engineer Tommy flowers in 1943. It was used as a codebreaker in World War 2 and to intercept German messages etc... 10 in total were created and were said to help win the victory in WW2. When the War was over all 10 machines were dismantled and every set of instructions, diagram and anything else related to the machine was burned to keep it all a secret.
the first video game ever made was called Cathode Ray Tube Amusement in 1947 which you may not class as an actual video game, as it doesn't use any programming or computer graphics. many other playable games were created soon after for example tennis for two (1948), NIM (1951), Mit tx-0 mouse maze (1959).
The games develop more and more in around 30 years from the Cathode Ray Tube Amusement in 1947 to space invaders in 1980 which is more memorable game and most of you will probably remember from your own past of playing games in arcades and at home, and its even a game that has been made into a game on our phone.
Many people in the video game industry were wrongly credited or got there ideas stolen by others for example Max Newman , who was a famous mathematician, wanted to create a machine like Colossus, he had problems with sorting out how it worked and getting it to work. he went to a machine company called Robinson (as in Heath Robinson) which didn't work as well as he wanted and it kept having problems that he couldn't solve, so he was put in touch with Tommy Flowers an electronic engineer in order to help solve the problems with the Robinson machine, which he did. He helped solved the problems with the machine and he ended up taking credit for making the the "Colossus". and many other incidents like this happened through out the history of games.
The game industry came a long way in around 130 years from the difference engine which was a massive piece of machinery that only calculated polynomial functions, to space invaders, a playable game that we all know today, games have come very very far.
Part two will be with you soon, Thanks!
References:
http://www.computerhistory.org/babbage/engines/
http://www.picotech.com/applications/colossus.html
http://classicgames.about.com/od/classicvideogames101/p/CathodeDevice.htm