There are small nuances that have taken YEARS for people to discover. It takes a long ass time to really “get” how it works, especially if this is the first YWG game you are really sinking your teeth into.
Here is a breakdown of how it works.
ALMOST everything you do increases rank. That literally means every single-individual bullet you fire, some shot types increase rank more than others, as well as the option types.
Dying reduces rank. That’s the only way to make the game easier on the fly. The trick is to keep rank from getting too high in the first place. And here is the dark dirty secret: Hold the START button when you boot up the game to play with a lower rank default. It isn’t considered cheating because nearly everyone does it.
Collecting small value medals (up to 1000), does not noticeably increase rank (but anything over 900 does).
Using a full bomb doesn’t increase rank, but using partial bombs does A LOT.
Collecting “special” power-ups, excess power-ups, full bombs, and 1Up/extend increases rank A LOT.
Increasing you firing rate (by tapping fast and then holding) gradually increases rank exponentially.