The 'blocks' or 'blobs' in Puyo Puyo are actually jellyfish. Despite the computer's random drop technique (described above) there are an amazing number of strategies for this game.
As 4-of-a-kind sets of a jellyfish-destroying reaction an effective strategy is to build alternating offset groups of three in such a way that destroying one will cause a chain reaction. This is particularly effective as Puyo Puyo rewards the total number of steps in a chain much more than the number of jellyfish in one explosion. So, if you build like this:
| |
|YX |
|YX |
|YX |
|XYO |
|XYO |
|XYO |
|YOX |
|YOX |
|YOX |
---------
...then it is possible to set of very, very large chain reactions. Creative players can also build this layering horizontally or using L-shapes. It should also be noted that an opponent loses control temporarily and all of his/her jellyfish freeze while your reaction is occurring, so this is also an effective defensive measure.
In Puyo Puyo 2 and upwards there is a large bonus for a player who responds immediately to an incoming rain of Jellyfish by counterattacking. This can make striking second a sound strategy.
Puyo Puyo is inhabited by all manner of strange creatures, including Skeleton T and Cait Sith, the Irish twin cats. Don't even bother with the American version (Dr. Robotnik), it has none of the Japanese charm of the original. It is widely available on PC emulator in a number of forms.
I love this game and I should point out that I am not a puzzle game player by nature, I tend to play lots of cutting-edge 3D stuff. It can be terribly, terribly addictive and should never, ever be played for 6 hours whilst listening to non-stop live Kenny Ken and drinking beer, as this can have serious health implications for you and those around you.