This is one of my first builds, but I think that it's pretty cool and I just wanna find some feedback on this build of mine.

As you can see, I go heavy AD and attack speed, with the phantom dancer and boots of mobility for twitch to have a crazy movement speed. The Bloodrazer gives damage, attack speed, and a way to kill tanks, and with your crazy attack speed, you should kill them real fast. The Bloodthirster is my main damagae output, as well as the item for life steal. The sunfire cape adds the health and armor to survive longer, plus you can do the trick of stealth and burn them while stealthed, which I find is a very quick way to kill creep and then do a crazy push with.
The Frozen Heart basically solves all you mana problems, as well as giving you ability cooldown, and making them attack slower to you.

I personally think that Twitch is the ultimate backdoor champ. I mean, how good is soloing a tower? AWESOME. For those of you that don't know, his ulti out ranges towers, and the cooldowns around 1 min at lvl 18. With his stealth and slow, you can run away from almost any circumstance after doing a massive amount of damage to towers late game. We were losing so many games, but because of me backdooring and pushing top, we flipped the game around to us winning. His ulti, with his super high attackspeed, he can literally attack in less then 3 seconds, then run.

I don't know any runes as I'm not lvl 20 yet, I don't have a real specific skill sequence, just that you should get expunge and his ulti whenever it's out, and that you should always be far from teamfights, enough to help out, yet not close enough to get ganked as he should be your teams main damage output late game.
Thanks for reading this, and please don't hate on me because I just wanna know what you think of a backdoor twitch.
Thanks.