Just tested; if anything, creeper tracks players
better laterally across walls on laser-guided than laterally across floors. Could not reproduce. Not gonna work on it unless I get more details.
edit: Here's my testing environment, just to explain how I was unable to repro and maybe add a clue to what the problem is:
The white bricks are raycast-off. The creeper and spawn are suspended on one pip of plating. On each of several tests, the creeper was able to reach me and never got to the top or bottom of the red wall; every single initial lateral move in my direction was necessarily one that went horizontally from a lateral neighbor. The red wall is featureless except for cracks on either end where the plates were wedged in; this did not give it any floor/ceiling surface to work with, however, and if it did it wouldn't apply to the two middle sections.
If the problem is really not being able to find its way around a huge obstacle, turn down the player-hunting until it works. Even laser-guided used to be quite literally a straight line, but I patched it to wobble a bit because it just plain stopped working in so many cases. There's not enough CPU to spare a bot-wars-style navigation behavior on top of everything else. That said, I don't think it should ever stop growing, so hypothetically if you wait until the creeper has splatted across the entire obstacle, it will eventually "spill over" (think of yourself as the only source of gravity and the laser-guided creeper a trickle of syrup). It might take a very long time, but the main factor is how well you designed your area (protip: laser-guided and lips/overhangs/pockets don't mix unless you
want players to try and use them to stall the creeper).
On the subject of people not having creativity, here's what I posted in the RTB thread's manual on how to play (which is now a little outdated, sadly, but Topic too old):
A temporary passage that gets closed up can be made by setting a transparent brick to no-collide. Alien spores in the space station's ventilation system! A monster from the deep is attacking the boat! Pod People (FreeSpawn, if you die you respawn once and try to kill survivors with a sword)! Fight your way out of the dungeon to the safety of daylight (with a switch outside that kills the creeper)! The possibilities are endless.
I never saw ideas 1, 4, or 5. Idea 3 was mine and I did do it. I *heard* of idea 2 from the suggestion for the global creep kill event, but personally I never saw it.
