Pretty fun! I really like the midi tracks that play. And as for your concerns about deltatime the game ran perfectly fine on my 60hz monitor.
Sorry to see you're not receiving much feedback or reviews on your game, admittedly we've got a lot of games to look at and don't have time to install entirely new software to open particular jar files. It's the nature of jams to always provide easy to open exes. I'm unfamiliar with j2me but it seems that it doesn't natively support the capability to make exes, I suggest looking into third-party "wrappers" that allows you to make it an exe.
Now onto the actual game, it's very lovely. I really had a lot of fun with it and I mean that. The midi tracks were surprisingly good and the gameplay, while simple, was fun to mess around with. You've definitely picked a very out of the box choice to develop your game in and I commend you for that.
Best of luck on this project! It's a cute game and I hope it can reach the full potential that you see in it!