Did something change with the mob spawning mechanics in 1.6.4? I'm running DW20 1.6.4 and built a platform very similar to what was posted, and mobs aren't spawning much - I have it built at 203 (sea level/ground in this area is at 64, so that means its 139 blocks above ground). After numerous MC days/nights, I have seen two endermen, neither of which I was able to kill, one due to rain, and relatively speaking, I haven't seen much of anything else. The start of the pad is placed a bit more than 24 blocks from where I stand, and it seems that at that point, the zombies still pick up on me and beeline for where I'm standing. Nothing else seems to care. It seems like when I come up the ladder, a ton of mobs spawn, but if I just sit there, they tend to despawn and very little continues to spawn. Also, it seems when I go down the bridge and get closer, mobs start to spawn more.... Any thoughts?