Don't ignore the suggestions!

My Problem

My OEM battery was swelling, pushing the whole screen assembly up on the left side.

My Fix

I used both the above guide and the reassembly video on YouTube. The repair went mostly like clockwork, but I failed to use the guide's advice and didn't warm up the case before pulling on the adhesive tabs. Just as predicted, one snapped. I had to pull the other one, then gently pry the battery up with my spudger until I could grab the tape with my tweezers. I learned my lesson - HEAT THE CASE!

My Advice

If you don't have the iOpener, here's a hack you can use. Get a household sponge wet and stick it in the microwave for 1 minute. Put it in a Ziploc bag, so that you don't get your phone's guts wet, and you're good to go. Works like a charm!