Got terraria to work on my potato laptop by setting It as high priority.
I'm about to defeat expert wall of flesh... Skeletron is a bitch and should be nerfed a bit IMO. I had to overhear to kill him, so the dungeon loot wasn't even as good as what I was wearing (I made full molten armour for the boss fight, but usually use shadow).
Also, the expert queen bee is brutal if you're not fully prepared.
I don't actually find expert mode as hard as everybody said it would be. I know some you tubers were dying to slimes and all of that stuff, but I haven't had many problems. Basically, if you take it slower, over prepare for everything, and be ready to teleport out, there's no problem.
Also, I got medusa's head on my 3rd medusa kill at the start of the game. Woo!
Also, there should be a key bind for the magic/ice mirror.