Nice job. Bit of feedback:

- I’d recommend having the crossword grid take up the full screen. If there’s enough width and height, you could start the player in the middle. That would give it more of a feeling of unlimited bounds which feels more appropriate given the free-thinking theme

- For rotating between horizontal and vertical, consider using a single toggle key instead of two separate keys. That would make it faster to work with, especially if it’s something that doesn’t require moving to the function keys (something like Shift + Enter).

- You might also want to change the UI color or add a visual indicator so you can immediately tell which mode you’re in. Right now, it’s not clear whether you’re about to type vertically or horizontally.