Pokemon Yellow is more or less the same as Red and Blue with some extras here and there. But it's just as awesome.
The main differance of this game is that you start out with a Pikachu, who can't be evolved into Raichu. But the starter Pokemon Bulbasaur, Charmander and Squirtle can be obtained from other trainers as you go from town to town. Pikachu will follow you around and you can talk to him whenever you feel like it to see how he's feeling. The way he feels makes no obvious difference to how he fights however, but it's a nice extra. Yellow was obviously loosely based on the anime' as Jessie, James and Meowth appear in places where normal Team Rocket members would appear. Normally towards the end of places such as Mount Moon, the Pokemon Tower ect. The frontal sprites of the Pokemon have also been re-designed to look more like their anime' incarnations. There are also some other extras such as a surfing mini game.
The main aim of the game is to try and complete the Pokemon league. You can have up to 6 pokemon in your partly at a time, they can be caught in the wild by weakening them and throwing Poke Balls at them. You can store a large amount of Pokemon in boxes at Pokemon Centres.
There are 8 gyms, each specializes in a differant type of Pokemon. for example Misty's gym in Cerulean City specializes in water type Pokemon and Lt Surge's gym in Veridian City focuses on electric type Pokemon. On your way from town to town a lot of other pokemon trainers will challenge you to battles, and you will have to cross forests, caves and rivers, whilst collecting as many Pokemon as you can.
In battle you start out with simple techniques such as Thunder Shock and growl, but as the game progresses your Pokemon will become ultimate fighters with skills such as Thunder Bolt, Hydro Pump, Fly ect. Pokemon learn new moves through leveling up or using TMs (technical machines) on them. HMs (hidden machines) can also be used to teach pokemon attacks, but the attacks granted through HMs compulsory for travelling through the game. For example you will need to learn Surf from a HM to cross rivers. you can only have four attacks per Pokemon so it is a good idea to research what moves a Pokemon can learn from sites such as Serebii or Bulbapedia and plan what moves should be learnt.
Like I mentioned earlier the frontal Poke' sprites have been updated to look like their anime' incarnations. The rest of the graphics are more or less untouched. However if you are playing this on a GameBoy Colour, the colours will change depending on where abouts you are. For example in Cerulean City the colour scheme goes dark blue in Lavender Town the colour scheme goes a purple colour. If you played Red or Blue on a GameBoy Colour the colour scheme would be the same throughout.
The music for the game is funky and debatably the best soundtrack for a Pokemon game. 8 bit music can be just as satisfying as non 8 bit music.
Red Blue and Yellow are all more or less the same game, but as previously mentioned this one has some differences. Aside from starting with Pikachu and being able to obtain all the starter Pokemon. Some Pokemon locations have been moved and the gyms, particularly in the later half of the game, have been made considerably harder.
If you want to collect every single Pokemon, you'll need a friend who has both the Red and Blue versions as you can't catch every Pokemon in Yellow. And not every single un-catchable Pokemon is available in Red you will need to also trade with the blue version too. (if that made sense :P)
If you haven't played this then go play it. Once you have completed the main story it's a lot of fun to go back and collect and raise any pokemon you missed along the way. It's a very lengthy game and you can easily spend over 40 hours doing the main story for the first time and you will be happy with this game for a very long time even after completing it. Very highly recommended.
Pika! Pika!
Milesprower 2k9 original reviews