Great job submitting a game! This is probably one of the cleanest "bullet hell" type games I've seen for Nokia Jam. It plays really nicely and you implemented the upgrades well, they have a significant impact on how the gameplay feels. I want to be able to see the player character before the level starts and I noticed in some of the later levels I couldn't see the vertical axis lasers before it started. It would be nice to see everything that will be in the level and where I am starting, even if it is in the center every time, so I can prepare my best plan of attack.
I found the second level to be the hardest. Once I got a few upgrades under my belt it felt like I had a lot of room for error and I could easily afford a full health heal between every level. It depends on how you want the game to play but I just thought I would share my experience. I like your use of sound to make the game feel frantic. Its satisfying to beat a level just to be free from the constant tick of sound haha. Thanks for participating!