I have the most trouble with Sniper Duel and On a Rail. I hate laying all the bridges, redstone torches and rails only to find out I was short by about 10 after riding the distance.
Maybe it's mods I'm using, but I can't even SEE a mob 50 meters away on farthest view.
The rest of them aren't all that hard to get.
ok hear me out dup the power rails and just make a really long line straight and just even if stuff gets in your way just knock the block on the ground and one above then keep goingthe hardest one for me is the pig in a saddle thing you have to him up then put the saddle on then dig under just 5 blocks and keep one block on the pig so he stays in place then have your friend knock down the one block and bam call it easy but to me it was really hard and most extremly annoying.
There's 4 achievements that are difficult for me to do. I can't really decide which one is most difficult though. Also, it's not that difficult to beat the Enderdragon if you have enough arrows to spare. And stay away from the edge of the mainland. I managed to do this on SMP but I almost did this in SSP but I made a really dumb mistake in hardcore mode...
*On a rail: It's not physically difficult, just very time and resource consuming
*Sniper Duel: It's a bit difficult to trap a skeleton but it didn't take me more than 20 minutes to set up/utilize in my hardcore map.
*Overkill: It's tricky to get a good enchantment unless you have a mob farm or do an unreasonable ammount of mob killing. 1.3 will really help this a lot though.
*when pigs fly: If you can't find a dungeon, then this achievement can't be done. Also, it's annoying luring a pig to a narrow ledge I made. Even then, sometimes the pig won't die if you don't calculate how much fall damage the pig can take.
On a Rail isn't that hard...I've mined stacks of iron and gold.
What really tires me is the Sniper Duel. I suck at shooting with a bow, I'm only good at close combat. And I'm stuck to Medium Render Distance due to my 32 bit Java, so it's basically impossible unless a mod was at the right spot where I shot.