Well for mobile, they added the auto targeting system. Pretty obvious. When you hot an enemy off screen, the damage number sometimes pops up on your character. For finding enemies like the twins before you spot them, zoom out but dont let go, you'll see the map but gameplay is still going, so youll see where the bosses are and which direction they are headed. Best bet is to build or mine a looooooong flat surface and make one layer Asphalt Blocks. So you can run back and forth super fast while firing up with a ranged weapon to tell you where they are while damaging them. To choose which enemy will be auto-targeted, tap on that enemie and the yellow arrow will switch from one to the one you tapped
Thanks TerraNova, and TealderII. That was helpful, though I find the whole auto targeting thing a little disheartening, like I am not actually fighting it myself. If I'm just shooting off screen at something I can't even see and the computer does the aiming for me, how much credit do I deserve for killing it after all? But I suppose those considerations are a little abstract.
After some trial and error (Twins despawned in the middle of my first fight) I eventually found that my best strategy was loading on some venom, regeneration, soup, and ironskin and just laying on my best melee weapons. For instance, Plantera seems to do much less damage with the bulb just sitting right on me than if I try to run and keep out of her way, especially since there is rarely enough room on my screen to see where she is coming from if I do. As long as I build a trench on either side of the bulb before summoning so the spike balls can't stay on me, I can take her out in a few seconds by letting her sit on me and just hacking away. Of course now that I have the turtle armor I don't even need the potions, but it worked fine with the potions before that, if that is helpful to anyone... Also, that strategy worked best in narrow spaces for some reason. I was using pretty much the same plan for the bosses too, though again it seemed a bit like I was exploiting a loophole? With the right potion combination they seemed fairly easy to take out?
In other news, I fixed a problem I was having where recipes weren't showing up. I eventually spawned all three available worlds for mobile looking for all the metals. Luck was with me because I now have access to all six hardmode metals, but none of my worlds had Corruption, only Crimson. I couldn't figure out why the crafting recipes for Mechanical Skull and Worm weren't available in my crafting menu since I had Souls of Night in my inventory (and I don't remember where I could have gotten them from, a Boss I assume). I saw someone had posted that you had to have a mythril anvil for those recipes to show up, which is why I started looking for all the metals in the first place. Well, that didn't work. Eventually I started looking for Souls of Night, and lo and behold I couldn't find them. All throughout the Crimson of all three worlds not a single Soul of Night would drop. Further searching ensued, and I discovered that in Mobile they would only drop on Corruption. With only Crimson worlds, I was thoroughly screwed if I wanted to ever fight Ocram, or craft more endgame things, but then, salvation! I remembered that I had purchased corrupt seeds from the Dryad during a Blood Moon and seeded part of my skybridge with them. I went up there...and the first thing I killed...a Soul of Night! Immediately the recipes for Mechanical summoning devices, the Neptune Shell, etc. all popped up in the crafting menu.
I covered all my corrupt dirt with stone and sand and then harvested it when it became ebonstone and ebonsand. I coated a prepared cavern with it just above my upper Hell level subway, plenty of entrances and water candles, and finally I can craft all sorts of things I never could before. Chunks of Flesh, Light and Dark Shards, Cursed Flames, and finally the stuff to make an Ahnk Charm... I read somewhere or other that this "glitch" of being able to buy corrupt seeds in a crimson world was being or had been fixed in an update, but I hope it hasn't because it really saved me. Otherwise there would have been no way at all to open those recipes and continue crafting.
And if that process won't work for other people, I did read a post from someone (where though?) who said that sometimes if a recipe didn't pop up the first time you picked up a new crafting material, you can get it to by dropping the material in front of you and then picking it up again.
