I finally got it on solo too. I only got my weapon upgraded to the three-shot, but it carried me through. I did get upgraded to the 4-shot near the end, but by then I didn't need it as much anymore because I was working through the chambers where you navigate through the little fireballs. I ended up ranking 10th in the world for 1 player lantern run, woohoo!
For me, the hardest part was with the three enemies that try to suck you in with their tongues. Whenever that came up, I wouldn't be able to free myself from all three in time to pull my lantern away. They'd just start sucking me in again. Also it would sometimes glitch and fling me into the mouth where I would get stuck in place. That was so annoying, but fortunately, I didn't have to face that section on my final run.
Last edited by Pirateogta; 08-17-2011 at 05:47 PM.