First of all, the game is beautiful. It feels both retro and certainly fresh at the same time, and I found it to be really nice. That being said, the gameplay is also great, and it feels like a retro arcade game from the 80's.
It's easy-to-understand, and the controls are what you would expect. The gameplay is quite dynamic, and it places a huge importance in dodging and shooting. Shots can also be angled and also bounce for better damage, and this makes the gameplay unique compared to other retro-style games.
The game also has a huge variety of enemies, each one having a unique attack style and function.
That being said, While the nostalgia factor here hits big on older players such as myself, this might not be as appealing to younger players. However, even without the nostalgia, I found that this is indeed a great timewaster. It doesn't need an internet connection all that much, and it does not feel P2W at all, so it ticks all the boxes for me.