The gameplay loop feels really nice, getting upgrades is satisfying and it's all very easy to understand and play.
It didn't feel a lot like a gameboy game for me tho, be it the gameplay (using only one of the two face buttons), the visuals(tons of sprites on screen, and a rendering look that doesn't really evoke nostalgia) or the sound (more chiptune than GB), there was always something a bit off.
Still, a great entry and a fun game!