I expect the game is designed with replayability in mind -- perfecting your score on those stages. It's just perceived as 'grinding' to these young gamers who think games are supposed to just be easy interactive movies where the goal is to get to the next big setpiece as quickly as possible. The pay-for-upgrades aspect was probably seen by the publisher, Microsoft, as a compromise.
If a 100% shotdown ratio isn't possible with the base weapons on the first stage, that's an issue. Upgrades should be something that have more value later in the game, but I'm getting the impression from these reviews that you need them from the onset if you really want to have a productive run. That means grinding the first few levels again and again.
If you want to stress replayability, come up with a unique scoring system, have branching paths with multiple endings, come up with some different ways the dragons/riders can interact with the environment that might alter the way things unfold... Stuff like that.
Moved the Crimson Dragon topic from General SEGA to this existing topic, given the game is not developed or published by SEGA.
Sorry, Barry. Didn't realize this topic existed. Figured since the game was Sega-related, it wouldn't be too out of place in the Sega forum.