东方栖霞园 ~ Blue devil in the Belvedere Normal Reimu 31.6 Billion

I've been watching some of the top level scoring plays in this game. When the game first came out, the 30 billion achievement was thought to only be possible on Lunatic, but with better understanding of the game systems and graze strategies being developed for many boss patterns, the achievement became more and more in reach.
This route I use is pretty much taken straight from lidera's 41b Lunatic run. You get a ton of graze from Remilia, but in order to further increase the Point Item Value even more, we suicide two/three lives into Artemina's final to graze the orange arrows and the red knives where they spawn. On Matthew we abuse hyper invincibility frames to supergraze the laser spell, as well as some tricky routing on the final to spawngraze the waves of blue stars. Lechat has the largest graze gain in the game with her final firing tons of penalty bullets, and it's this along with good Stage 5 and Stage 6 performance that allows us to then gain tons of score in lategame.
To elaborate on the scoring system for this game: Once you have 4 full crystals, you can press X to activate a Power Overhwleming (hyper) which will make patterns harder, but also makes it such that on stages, enemy kills increases chain more (which increases the multiplier more), point items are worth twice as much, and on boss spells, capturing a pattern in hyper mode grants doubled Spell Card Bonus, drops double-value point items, and grants extra score in the Stage Clear bonus.
As such much of the game revolves around routing stages exceptionally well to kill as many enemies in hyper as possible, which I screw up badly in Stage 5 and 6 in this run. Dying or bombing is also very bad, as it makes the multiplier go down. I make several mistakes in this run, so the actual score potential is much higher than this, but this should go to show the relative ease at which this acheivement can be done. It's much more important not to mess up the stage sections than the boss fights, though both are major sources of points.