Thank you very much for this feedback! 30 Points is amazing, so likely you didn't keep going just due to already having a really good high score, in a high score based game. Though I would like to respond to your issues.
1. The hitboxes are actually a tad bit smaller than the actual images, though seeing as multiple people have complained I will shrink them.
2. The trail was actually a bugged that happened right at the end due to the web export, but in the testing it was working.
3. Honestly without the trail, I do very much so agree with you. It was really the main way I made it feel good in testing and without it, it really does numb the experience.
4. Honestly people have been using the pause in a similar fashion to that (something I did encourage by calling it dodge down in the description), but I do understand what you mean, I honestly did want it to be as simple as it was.
5. The 30 seconds of gameplay to experience the whole game is very reasonable, but for a Jam, most people aren't likely to play for more than a few minutes, it was also with a "lack of variety" just due to me not really knowing how to add good variety, more enemy types is just the same game but with slightly more, and that didn't feel all too creative.
6. Yeah visually I didn't really have a style till the very last minute, which made it very difficult to do it well, but I just tried to keep it as simple, and as clean as possible, but yes that is a point I should've improved on.
Honestly I feel like a pretty major reason you also didn't have that much fun was just due to scoring well at the start, it's a game meant to challenge you, and getting 30 points in the first few runs kind of fights that purpose, but I can completely, or partially agree with you on all of these ideas, thank you so much for rating it honestly, I hope to make it more enjoyable for my next game!!