Very nicely done for your first game! I think Breakout/Arkanoid was my first game in Unity as well.
There were a bit of weird physics things, but others already pointed them out. Solid game. I wasn't able to beat the first level, but I also just don't have the patience for Breakout without some powerups like Arkanoid.
Interesting historical note: Steve Wozniak and Steve Jobs worked on the hardware for Breakout in 1976 before they founded Apple, and some of what Wozniak developed for the game was implemented in the Apple II computer.
Nice job overall for a first game. Congrats on publishing it for a game jam!