This gives me strong Cartoon Network flash game vibes and I am loving this nostalgic trip.
Unfortunately my Laptop did not vibe with it that much: I had pretty low frame rate, the lawn mower was pretty slow and each second on the timer was about 6 seconds in real life! I could not tell you why exactly - all the stats on the Task Manager seemed fine - but it did have something to do with the grass is my guess, because on the grading screen and the main menu I have 0 issues. One other thing is thing is that I would've really liked if the player sprite had some visual mood changes (for example cheer when you dash or sad when you run over animals).
From the gif that you provided, the feedback you've gotten and the game play that I have enjoyed in 1/6th speed I can tell that this is a fun and frantic game. I would've enjoyed if you found some way to incorporate "Mode". Still this is a very enjoyable and complete game, congrats :)