Well, these are the original games that started it all. The game began as an idea a man got catching bugs in his backyard and has become a cult hit. Spawning a TV show, movies, comics, toys, and even more games. And it all came from two small games that Nintendo did not expect to sell very well. It's also the inspiration of this site! (Obviously.)
Graphics: 6/10
OK, so the graphics aren't a strong point. Not even James Bond 007 was this scarcely detailed. All the sprites are the same height and are iconic, in that they have big heads and little bodies. The monsters are pretty detailed, but there's little sense of how big they really are. What's worse is the fact that your Pokémon on the battle screen is zoomed in and pixilated. Boo! Everything else is standard fare. The buildings look the same except for various signs and how big they are.
Control: 10/10
Control is dead on precise. Of course, this is Game Boy and the controls are usually dead on anyway. There's very little for you to do. You walk around, look at stuff with A, cancel with B, and pause with Start. Everything else is done by menus. Simple, just how I like 'em.
Sound: 5/10
Sound, in one word, sucks. There are a few catchy tunes (Opening theme, any battle theme, etc.) but most are annoying, like some of the Route music and especially the music in Lavender Town and Pokémon Tower. The remixed MIDIs you can find on the web are much better. Luckily, nothing in this game relies on sound, so it's OK to turn down the volumne.
Story: 2/10
You are a young trainer (default name is Ash, but you can name him anything you like.) from Pallet Town. When you reach the age of 10, you decide to traverse the land in order to become a Pokémon Master. Your rival is trying to stop you as you collect the neccessary 8 badges and raise strong Pokémon to beat the Elite Four. OK, so it ain't Tom Clancy. So sue Nintendo. (Note: THAT WAS A JOKE!)
Gameplay: 10/10
Here's where the game shines. You wander around the countryside, searching for Pokémon in tall grass. Professor Oak gives you your first Pokémon and you have to collect the other 150 species. You capture these creatures in Poké Balls. Upgrades become available during your adventure. Some Pokémon, like Pidgey and Rattata, are easy to find almost anyplace. Others, like Mew and Zapdos, are very rare and take a great amount of skill to capture. In order to fight against the Gym Leaders, you must train your Pokémon by making it fight against wild Pokémon. Each Pokémon is represented by one or two types. These types have a great effect on which Pokémon you should send out. For instance, Electric-types can't harm Ground-types, but those same Ground-types are super-weak to Water-types, who are weak to Electric-types. Get it? Also, it matters what attacks your Pokémon knows as well. An Abra may have an advantage against a Muk, but it will fall unless it knows a Psychic-type attack. Level also plays an important role in the thick of things. A level 60 Oddish can easily beat a level 10 Chamander with just Absorb, even if Charmander knows Fire Blast. There is a great amount of strategy involved, as Pokémon can learn a multitude of attacks that you wouldn't think it would learn. Pikachu can learn Surf, for example, and Blastoise can learn Earthquake. Each Pokémon has its own stats as well. Attack, Defense, Speed, and Special. However, you can never control your Pokémon if you don't have the specific badge to control them with. Trading is an important part of the game as well, as each version has 11 species (Minus Mew) not in that particular game pak but in the other. For example: Mankey is only available in the Red Version while Magmar is only in the Blue version. When you collect eight badges and raise a powerful team, you must face the greatest trainers around: the Elite Four. Once completed, you must then face the awesome power of Mewtwo.
Overall:
Overall, I think Pokémon Red/Blue is a good starting point, even though there are glaring flaws. Those have been fixed by Gold/Silver though. If you're just starting out, and Gold/Silver is unavailable, these games are the way to go. Remember, you gotta catch 'em all!