Alright, so me and my friend have been 1v1'ing each other every now and then and he (we are both pretty nooby meleers) got this strategy to keep about ~12 valkyries around and patrolling the entire map in order to blast away any overlords that I have. I have no idea how to counter it. Anyone know something more than I do? Keep in mind ~12 valks completely obliterate overlords in like two seconds. I had tried hydralisks but whenever I put my hydras to defend it, he either managed to run through them or go around them to my overlords.

Please and thankyou!

If you're willing to practice your melee according to normal, non-nooby build orders, then you will be able to easily counter those 'noobish'ness without much effort. But this in itself, is usually hard for a lot of people. 12 takes a lot of time to build, and by that time- even if T rushes 12 valks, any decent Z will have around 5 groups of hydras, or countless zerglings- which will own T because T is doing stupid stuff like that.
But if you want an instantaneous effect, Valks die well when faced against scourges.

If he's spending THAT much on Valks you should have ample time and resources to assault him on the ground. I think your macro is probably lacking from the sounds of it.

Post replays if you want maximum help!

Alright alright, but keep in mind that I'm not a pro or anything, and there's plenty of things that (even in watching it) I saw I did wrong. Plenty of moments where I could have won. Keep in mind that we had a "no rush" rule in effect.

Quote from Excalibur

If he's spending THAT much on Valks you should have ample time and resources to assault him on the ground. I think your macro is probably lacking from the sounds of it.

Indeed; if the Terran gets more than 2/3 valkyries then you are doing something wrong.

He only had two starports, he did it over the course of the map. He didn't do it all at once. Watch the replay! You'll see!

You are honestly both so horribly awful that you're not even worth helping. Dear lord. You may want to do some reading if you want to learn a bit more about how to play the game.

I was amused. Use spore colonies, hydralisks and don't keep them all bunched up.

Q.Q

Your three biggest mistakes:
1-[ You sent trillions of zerglings against a ton of units with splash damage ]
2-[ You had no upgrades ]
3-[ You had no anti air ]
ONE- Next time, if you have so many zerglings, don't send all of them out like that, send them one by one to scout. Find the smallest expansion and kill it.
TWO- If you actually consider sending in those lings in a group, upgrade to the max.
THREE- As soon as you know he has valks (or even before) make anti air around the cliffs of your bass, that solves many problems.
ALSO- If you are going to make guardians, at LEAST have some devourers/scourges escorting them.
Here is a simulation supporting the extra reason.

I'm no melee expert, but here the whole game in a nutshell: Proper Scouting.
Some other flaws I've seen:
-He went 2 rax and 2 fact in a ZvT. I'm pretty sure Ling muta could rape that. You did go ling muta, but you failed to use ovies to scout mines properly
-He had NOTHING by the time you had lings out, with proper scouting the game would have ended quickly.
-You were scared to expand, I only saw you expand to 1. Thats nice but, against a Turtle Terran, expanding is the best way to take advantage of the situation.
-You're too micro intensive. Bases need love too, while sending your microing, you need to macro as well. That 2000 mins would have been spent on: Upgrades, troops, or even OVERLORD SPEED. Which brings me to....
-Death of Overlords. The best way to contain a splashing killing overlord death is to expand them across the map, while also giving speed and ARMOR UPGRADES.
-You had no upgrades. In the long run, +3 rines WILL rape 0 up lings and hydras, NO CHALLENGE.
-Defensive lurks: Nice but, with your final attack, bringing the lurks would have made a difference. Simply divided ling and hydra troops wont do squat against MnM +bat.
-I had no idea what queens were for.
-If you did expand overlords, you might have scouted the valk threat, therefore making hydras to counter.

That's all I remember from a x4 rep. Once again, you needed to scout. I cannot stress this enough. All of your flaws began with not scouting with a drone properly. Ovie scout is nice but, not fast enough to figure out opponent build and correspond directly. I hope this helps you succeed in your next battle.

I'd take a nice irradiate over a valk.

Another great thing to do is burrow some lings near all of the minerals to prevent the enemy from expanding, in fact, nuetralize the enemy by rushhing in, destroying the command center, then burrowing a ling. If you are able to do that, then the enemy is screwed.

Mass lings at start isn't really effective unless your opponent is a complete noob. You'd simply get owned by tech to come. It would be better if you only used lings at start to scout and harass- and tech up to whatever effective against a certain race.