I don't know how to get past this section :(
Yeah unfortunately we had a bit of a last minute bug with the cursor so it's tough to see what's going on at times.
For this area, you're going to want to double click on Cthulhu's cultist (the little guys walking around) and then double click on that cylindrical sacrifice stone on the ground to the right of the gate. Repeat for both of the followers and the gate should open :)