Yeah, I just see one of those games on Mosi and realized that transparent sprites can be used that way, but that's just my wishes for the game engine. As for custom scripts, they either don't work right or I don't understand something, but the game just doesn't start when I want to add them. If I could figure it out, I might write simple {get-palette-in-room}, {get-sprite-color} and {get-music-in-room} so as not to create extra variables for such needs.
A custom script for {get-palette-in-room} could just be:
return game.currentPaletteIndex;
I believe. It needs to be javascript in there and the 'return' is there as that's what a javascript function sends back. It does send back the index though, so if it's the first palette it will send back 0, the second will send back 1, etc.
The two main objects that hold information in Môsi seems to be 'game' and 'context.' If I look at the 'context' one, I believe the following should return the color of the sprite:
return context.sprite.colorIndex;