http://www.eternagame.org/game/puzzle/6503034/ stops after I alt-click bases 20 and 21 as instructed. The “Next” button does not appear. I can click those bases all I want to no avail.
I was able to solve it, but I don’t know what it was trying to teach me.
Glad to hear you didn’t get stuck. I agree, the tutorial doesn’t seem to be what was intended. Thanks for the report – I’ll bring it to the attention of the tutorial developer.