Really cool game ! The art is lovely the sound fit well & the gameplay is simple but chalenging.
Got me going "ok... one more try" quite a few time ^^
Tiny nitpicks to improve the game :
-Don't make the player go through the menu again to replay (reducing the number of actions needed to restart a game help a lot in keeping the player engaged after he dies)
- Make the first fox spawn a little bit earlier. there's a good 10 seconds of waiting at the start of the game. You can bring it down to like 4-5 seconds so the player have just the time to get familiar with the movements. You can even make it 1-2 seconds after a retry, throw the player right back in the action.
-maybe a little anticipation frame before a fox jump so you're not taken by surprise (make them bend their knees or squish them down ?).
Apart from that, really solid entry & fun to play. great job :)