As is the case with most slivers: the deck's objective is to get as many slivers on the board as possible as quickly as possible. The more slivers are on the board, the more powerful and flexible the options provided by each become. It's hard to compete against an army of unblockable slivers, each of which deal direct damage when attacking, can transfer their attacking power to their comrades, and have been pumped to gargantuan size, etc. This is, of course, why Sliver Queen is still the best sliver commander: slivers work best in large quantity. The difficult part here is managing the early game. This deck strives to overcome the low mana diversity and the low defense disadvantages inherent in sliver decks, and it's been fairly successful over the last two years (and with recent updates).
To explain the disadvantages inherent in sliver decks:
1) Mana is especially difficult with a Sliver Queen or other five-color commander deck in which each color is nearly equally represented. Chances are, even with an average creature converted mana cost of two, it will be turn three by the time you have your first 2/2 out, as you'll either have the wrong combination of lands in your opening hand, or the more powerful non-basic lands will come into play tapped or otherwise not be available immediately.
2) Keeping the first few slivers alive is essential, as the whole point of slivers is that utility provided by each increases exponentially with each other sliver under your control. So you won't be able to throw up much defense early, and you'll be susceptible to low power removal as you use up all your mana putting out creatures.
3) To a lesser degree, Sliver decks also run the risk of failing to maintain flexibility as a result of all their power coming from static or activated creature abilities. (You need lots and lots of slivers, which means less room for removal, counter, or other control).
To explain how this deck overcomes those disadvantages:
1) Maximize the green options. The mana-providing slivers are green, and all the non-sliver creatures are green mana givers. For this reason, there are more forest-providing lands than other types. This helps accelerate the mana curve. The cheapest pump slivers are also green, so we beef things up more quickly when we get them out earlier.
2) Keep the average sliver converted mana cost low. Some of the most powerful slivers are not in this deck, because they slow the performance curve down too much. If we started with 60 health, I'd put some of the more mana-expensive ones back in, but against the average aggressive commander deck starting at regular EDH health, we need to be playing little guys quickly.
3) Maximize chances that Sliver Queen is out by turn 5 via high overall land count and high percentage of mana-flexible non-basics. Sliver decks have to balance this objective pretty well with 2 above, and this one walks the knife edge well in my experience so far. Also, If she's not out by turn 6, the deck is going to offer you another option for a high CMC sliver by that time, and you'll have that creature's powerful ability to exploit, instead. Backup option not as good, but not bad, either.
4) In the middle and late game, you ought to be able to continue putting out two decent slivers or one high-power sliver per turn. The supportive draw engine is weak in this deck compared to emphasis on the three strategies above, but the draw engine is still there (Wild Pair, Staff of Nin, and, of course, a few of the slivers).
