How did old Cassiopeia play?

Old Cass was when everyone can burn about 60% of enemy's HP with one lazy Q or W.

Pretty much exactly the same, but her Q hurt more and her E didn't have a million extra goodies tacked onto it.

{quoted}

I only ever played her once before her rework, but i was low leveled and in aram so i really dont remember.

Well, there were two ways to play her. Either level up the Q (poison) first, or the E (twin fangs), or even both. Most people opted for the Q, since it had higher AP ratio, better range, gave you mobility, great harrassing power etc. Q exploded faster, and had a smaller range though than currently, less cooldown too. So it went something like this. Lvl 1 Q, lvl 2 E. At this point you would start spamming Q, getting the enemy to at least half HP. You had Deadly Cadence (the more spells you cast the less mana they cost) so mana wasn't really an issue. You'd start walking forward, but not really make any serious movement, back and forth,back and forth, truly like a snake, lulling the enemy into a false sense of security... then with a well aimed Q hitting, you would dash forward and unleash hell upon the enemy with Q+E+E+E+ignite, and you'd get first blood. lvl 3 Q, 4W, 5E, 6R, 7Q, 8E, 9Q.

At this point you were a force to be reckoned with. With a well aimed ult and fast reflexes you could down two non-tank champions without problem. It was always hilarious to kill the ganker AND the mid against you, then walk away with half HP. As for middle and late game? Cass was really fragile, so she stood back from the fighting until the odds were in her favor. Since Q had a +0.9 AP ratio, she'd spam Q weakening the enemy, then if they dived, she'd use her ultimate stunning, then poisioning as many people as possible while spamming E. I must mention that hiding in bushes with her ultimate up waiting for a lone champion or two was always tons of fun too.

For items it was typically: Rabadon/void staff/archangel (core, non negotiable) Also liandry+rylai worked wonders with her poisons, especially against tanks it was disgusting. So I always made sure to pick Cassiopeia whenever I saw 3+4 tanky champions in the enemy. Late game with a couple of Q's powered with liandry/rylai you could easily corrode their HP to half before the fight even begun. Also here's a funny flowchart, that's sort of true http://www.demaciancomics.com/albums/userpics/10824/cassiopeia-flowchart.jpg