Faithful 8bit metroidvania. With different biomes and all that. I’d say it’s even a bit too faithful, to the point of being boring.
It’s also very hard to figure out what’s going on due to the 8bit style. Is that a platform or the background? Will that projectile pass through the platform or not? Can I shoot down that projectile? The only way to know is to die trying.
The game uses progression system that I remember from some Zelda games: you need to buy a key item or character to progress. But first, you need to find a purse large enough to hold the money.
First boss is an acrobatic one. You can’t shoot it. Instead you need to jump avoiding its attacks and press button that drops a bomb in its mouth at the right moment. The following bosses are standard, though. You just shoot them until they die.