Yeah, collision is weird in Albrook on miniSphere but I never thought it was something with how collision is handled by the engine itself - KR breaks so easily I thought something very specific about the way it's coded made it not work well. Even in 1.5 KR likes to have other random issues. That game is one hell of a clusterfuck.
versions of Sphere between 1.10986... and 1.5 as well
I wasn't the one who coded the madness, but I do remember layer switching being present. I believe it's how it handles lower and upper floors, so you can be either on top of or under a bridge, for example. I think it's supposed to switch layers right between going from the dock into town too, but I'm not sure.
And the problem wasn't albrook, the problem was that I'd drawn my sprite scaled at 50% but not scaled it's collision polygon.
Hopefully you'll have a lot more performance headroom to do collision detection and such once I get CC working. That said, you don't need to check every single polygon every frame, only the ones you know are in range. See miniSphere's tile collision code:https://github.com/fatcerberus/minisphere/blob/v4.8.4/src/minisphere/map_engine.c#L1284-L1304