ok, the combination of ammo types is really interesting, but the level design and enemies didn't make that much of a challenge worthy of such an amazing weapon...and the ammo types working on a number limit made it too interesting to just spam the default ammo(that can also be fired too fast)…maybe an cooldown system would make the player want to spend the different ammo types more often. (i defeated Yuyuko with 3 shots, combining spread, homing, and explosive)
overall a very fun concept!
also....There are no trains in Gensokyo!