Option 1: Edit your last.txt file to have...I think it's 12? Might try 11 and 13 also. Then start a new character and choose "repeat last build". This will trick the game into letting you use Deadshot. (each skill has its own number) Option 2: Wait for the next patch, when it is getting officially re-added, with more than 3 levels and more interesting stuff to do with it. Option 3: Hug a Diggle. This won't get you the achievement but it will make you feel better.
Just fair warning: there's significant potential that Deadshot (and the new weapon skills) won't make it into the very next patch -- it might have to wait until 1.14. It depends on how long it takes David to do all of the huge slew of icons deadshot will require, I do believe, and he's quite busy on Clockwork Empire graphics and development at the moment. I was told at the beginning that the goal was 1.14, but that was before the Hugely Long Steam-Time Delay of Doom...but I still wouldn't count on the updates coming before, you know, Easter. That said, getting the achievement only really counts if you do it with legit content, and the legit content is coming. Just be patient.
http://community.gaslampgames.com/threads/deadshot.3280/#post-35143 This post has a save and a .txt. for you. I just edited the skillDB to put it back in. It's only like, 3 skills so it takes no time at all.
