Hi. Thank you for your feedback.
I was able to replicate the issue you experienced in Rainshower, and yep, it's definitely a bug :( I've fixed it now and uploaded a new build.
I wasn't able to replicate your issue with Donkey Kong 3 (testing on PC and Android). I was able to play without any issues, even after scoring bonus points when a bee reached Donkey Kong's side, which I thought might be the issue. But it worked fine.
I did manage to freeze the game once when I accidentally hit the "Spray" button of controller 2, but that should happen since it's meant to pause Game A (see page 13 of the manual). Pressing the Spray button on controller 1 successfully resumed the game as expected.