it's water.

fps is 200+ (or 80 in full screen mode) @ 1024x768x32+4xAA on my GF 6800/AthXP2600+, fps is perfect, really, bloom and other fullscreen shaders seem to have no impact on the framerate at all.
though the engine is really unflexible when it comes to programming issues, it supports only a quakescript-like language, but it's fun to play with.

the issue with the wall texture is true. it has some minor seams, but the greater problem is the octree-blockonly structure of sauer. the hieghtmap feature is rudimentary and you don't believe how many edges and corners i had to pull to make iot that "smooth" at it is now.