My favorite is probably UFO's system because it demands quick decision-making ability, to name one. Planning is vital for the playthrough to succeed, it's all up to the player to choose which bonus should they use to aid the journey, be it bomb, score, or life points. However, there is always a chance for some misses in even the neatest planning. That being said, players need to adjust their strategy to match the situations they face, no matter how spontaneous the process is. Sometimes, you need to divert from your planned route due to the aforementioned misses and proceed with the-best-possible-strategy (you could get) to reach the goal. It's not easy to do so, but if you did it right, it would give you something to be proud of to yourself.
Planning, decision-making, and executing. UFO system might be not all pretty, but it certainly has a special score in my list.
The special score might be due to UFO being my 2nd danmaku experience after PoFV, but it's still cool either way.
Gimmick for future games that I'd love to see >> Hmm, maybe ability to deflect/counter enemy's bullets?
