1 - In certain rooms up and down arrow will result in diagonal movement. Codename: Iceman has this in one or two of the beach rooms at the beginning. it's subtle, but saves a lot of up-left-up-left movement to get through a narrow 45 degree angle path.
In the Rm properties, assign values to vanishingX and vanishingY. They indicate where the vanishing point (
https://en.wikipedia.org/wiki/Vanishing_point) of the room is. Pressing up will make the player walk towards the vanishing point, pressing down will make them walk away from it. (Assuming it's all hooked up properly in the SCI0 template - not sure it is because it was based off LSL3, which maybe didn't use this feature.)
Typical values might be
vanishingX 160 ; right in the middle
vanishingY -200 ; 200 pixels above the top of the screen
You could probably make the player walk at close to 45 degrees if you placed it way off to the side, like I dunno, (-1000, 1160) or something.