Oshiyoseru is a single-screen arena shooter with slight RPG elements, where the money gained from defeated enemies can be used to upgrade your ship's maneuverability, speed and weapon configuration. Collecting gold (the yellow squares) increases your ship's level gauge, and once that bar is full you will earn a couple of upgrade points to use on improvements to your ship.

I can't read Japanese, but through trial and error I do know that the first two upgrades deal with bullet speed and spread. Players can choose to upgrade their ship evenly in all departments, or spend all of their points on a single feature (which will end up costing more).

If the idea of upgrades in an arena shooter tickles your fancy, then you should grab Oshiyoseru from here.