Colorblindness is mainly an issue for red and green, and even then colors can be discerned by how light or dark they are.
I did a run through Lusuria again, trying to see it as a first time player. The hidden areas are really well done now that I think about it. The implication that there is something more tragic behind the scenes meshes with the music to produce a rather subtle vibe that raises intrigue as far as the whole plot is concerned. There are some things that can use a bit of polish (mostly things I added after it was already done, like text box typing and character "voices"), but on the whole it's quite good. The town should really have at least some music though.
Spids needs the "face target" boxes checked though. There's a game breaking bug that happens on very rare occasions where the line charge sends Spids off the screen completely, causing him to disappear, but facing targets seems to prevent it...I think. It's pretty rare so it's hard to be certain.
I made a open demo for one area I'm making, since it's more or less self-contained for now - Akashmandir, the Mountain City, to the East of the Tower. The "flavors" for the four worlds are Eastern (Tibetian), Northern (Nordic), Western (Standard European fantasy), and Southern (some kind of desert Near Eastern flavor, ancient Persia or something, I don't know). I'm kind of building them all at once. The Tower itself might have its own town, maybe modern or futuristic, but I haven't started with that yet.
EDIT: I added a few new text tags to make handling text boxes easier. [wait=30] simply pauses the typing for the designated number of frames, much more convenient for pauses in speech than messing around with [speed] tags. [next] clears the text box after hitting space and then continues typing, allowing you to make multiple text boxes in a single event. This also allows you to create multiple text boxes in the basic player interaction text. Unlike other tags, these do not require a closing tag.