This game was definitely different from the other games I've played from this jam, and it was somewhat fun to play for a while (I'm not sure how fun it would be to play it for a long time, probably more fun because then I'd have time to better figure out the values of shells), but I wouldn't have time to play each game from this jam for a long amount of time (I've got through roughly ten percent of the games).
The walking by jumping worked well, and so did the art in the game. I think the main menu's scrolling background was a bit weird, and on the credits screen it's a bit hard to read the text when the background is moving all the time.
There's not much audio, but I like that on the main menu going up an option plays one sound and going down makes another one. But after playing the game for a while, I wanted to turn down the volume of sound effects, and that can be done from an option in the main menu, but not after starting the game. It would have been nice if I could at least get back to the main menu without having to close and reopen the game. But compared to games that don't let me adjust the volume of sound effects and music separately at all, that's still a huge improvement.