This is such a creative idea—wow!
I really enjoy playing board games, but having to read through instructions first can feel like such a chore sometimes. You did an amazing job explaining the tiles and showing where the character will land during gameplay. Why not build on that and highlight the current stage of the turn by blinking a white background behind the current objective (like character selection or tile selection)? Since it's a virtual game, you have the freedom to explain things in ways traditional board games can't!
Personally, I’d make the game a bit shorter—a flashy 5–10 minute experience. I know the goal is to survive as long as possible, but you could crank up the difficulty: less HP, more damage! 😛
I could totally see this being played by 2 (zombies vs. humans) or even 4 people, all planning their moves together!
Overall, fantastic job!