Number of keys showing
When describing problems, always mention your OS and game version (shown at the bottom of the title screen).
If your keyboard has USB or MIDI ports, there is a tremendously high chance (>99%) it will work with Synthesia. See what you'll need on the keyboards page.
If your keyboard has USB or MIDI ports, there is a tremendously high chance (>99%) it will work with Synthesia. See what you'll need on the keyboards page.
Which option do you have selected from the zoom menu (with the magnifying glass icon)? If you'd like the exact same view presented each time, you should choose "Custom" from the bottom. That disables snapping to even the white keys and remembers the exact values between songs so you can get something very precise.