Really cool concept overall! I loved the gravity mechanic, it makes moving around feel super dynamic and different from other games. The whole unstable reactor idea with upgrades that both help and mess you up at the same time is pretty clever. It was a bit confusing at the start and I had to figure things out by playing, but once it clicked, the gameplay loop got really addictive.
The pixel art and reactive music are a nice touch too. With a clearer tutorial and maybe more impactful upgrades, this could be something really special. Great job!