Graphics

CRT Simulation
In the settings, the player can enable or disable an emulation of a cathode ray tube monitor. This adds a bubble effect to the screen and rounds out the monitor corners. It also adds a hazy glare, a slight trail to moving objects, a pixelation effect, and a border around the game monitor similar to one that would be seen on an old computer.

Colors
There are two color schemes. The four-color one has white, black, cyan and magenta. The 16-color format has white, black, light gray, dark gray, red, crimson, brown, light yellow, light green, cyan, cerulean, blue, purple, and magenta (one color is missing from this list, I assume).

Saving Icon
When a player rings a Bell, a small icon appears for a short time in the top right corner of the screen. It's a blue floppy disk with a rotating clock hand. This icon can be disabled in the settings.