For a first game jam, and a second ever game, it's pretty good. I liked the concept, and the graphics were nice. Wish it had sound effects though.

The real issue is it takes too long for the game to get interesting since there's so few bullets shot out at first, and afterwards it's only fun for a while before it starts to get repetitive. Maybe add other bullets with different bounce types, or add walls that change how they bounce after a certain time?

Overall, it's pretty decent, and still quite fun.

I really like this, it's especially good considering it's your first jam. I liked the mechanic of bouncing bullets rather than really wild, crazy patterns.
One thing to consider is the difficulty curve - even on hard mode I found myself pretty bored for the first 20-30 seconds. Perhaps starting by having 5 or 6 balls shoot out right at the beginning? The most fun was between about 45 seconds to 70 seconds, so if you can figure out a way to get the player into that window faster that would be great!

Nice work on this!