Part 12: Bonus How To Fail At Lighthouse
Also, is there any way to replenish your supply of lenses, or is there a limited amount of times you can use the teleporter at the lighthouse?
Each time you want to use the portal machine, you have to replace the old, burnt-out lens with a fresh one. You may notice there are only three lenses; therefore you can only use Dr. Krick's machine three times.
Since this is my only way of reaching the other world from this one, I can make at most two trips back to the Lighthouse before I'm stranded. (I can sneak in a third if I use the Dark Being's portal at the beginning of the game. He only does that once, though.)
What happens if I run out of lenses? I'm glad you asked!
Fresnel lens, power modulation tube... same difference.
This is a genuine, bona fide Game Over screen, the first we've encountered. It triggers if you return to the Lighthouse after using the last lens, or if you let the last portal burn itself out while you're in the Lighthouse.
So that's that. But there's an interesting exploit I discovered recently. The lens burns out (and the portal closes) four minutes after you start the machine. However, if you turn off the machine before then (such as by flipping the switch in the gizmo here), the lens is undamaged! By using this trick you can make far more trips to the other side than you normally could.
Of course, you can only power down the machine from the Lighthouse side, so you have to keep your trips under four minutes long. But.. that's a surprisingly long time limit. Once I've cleared all the time-consuming puzzles out of the way, I can actually go from the portal on the beach to the Temple and teleport back to the Lighthouse before the lens burns out.
Theoretically, if you moved quickly and did one thing at a time (motor maze, cuckoo clock, etc.), you could retrieve Martin's pendant and acquire the crystal bottle without wasting a single lens.
There's not really any point to it, of course, but you could do it.