Acid Splash doesn't work on Large creatures (and more extensive Range problem)

There's probably some problems in how Acid Splash determines if two creatures are adjacent because it's impossible to target two adjacent Large creatures:

And this might be part of a bigger issue because many spells have problems calculating the distance between the caster and the target. This is particularly evident with Poison Spray: you can use it on a Large creature unless you are adjacent to it, while you should be able to target it even while there's a square in the middle.