So overall, I like your game. I think the 2 stages both last a bit too long to be fully enjoyable, 20-30 seconds feels like the sweet spot to me. Additionally, I think it would be more fun for the second stage to be a bit more populated instead of just the duck and the bullets, given how much there is to see on the first stage.
I would love to see how you update this game in the future, because the idea is very fun.