i beat Plantera, got the key, and ran to the end of the temple. It comes to a dead end, with the altar in a seperate room just out of reach. I've disabled all the traps, looted all the power cells, and dug around the entire temple looking for another entrance. Is there some trick I'm missing to getting inside?
That's just a random spawn issue. About 15% of the time I run into that wall keeping me out. Just gotta reroll a world. Most don't have that wall. If they fixed the Chlorophyte Drill being able to get through then that's really your only option. There's no trick there, you can do that fight in any mode of world.
Once again snatching defeat, From the jaws of victory.