According to the backstory of thegame, some "Outsiders" had it rough when they got transported to Gensokyo.
When Mikoto got transported to Gensokyo, she was still sleeping in her dorm. When Mikoto opened her eyes, she was suddenly in the sky, experiencing a free fall without any kind of foothold. Fortunately, Marisa was there to save her from falling to her death. One can only imagine what would've happened if fate refuses to let Marisa meet Mikoto at that time.
Kuroko Shirai's experience was somewhat less unfortunate, but still no laughing matter. Just like Mikoto, she was sleeping when she got transported to Gensokyo and found herself falling to Misty Lake. Unable to swim her way to the surface due to being in a state of sudden shock, she was saved by Sakuya.
Ruiko Saten, again, got into trouble for chasing an urban legend that said Gensokyo can help increase her ability level. This is long after her experience with the Level Upper and her swearing to not use any "shortcuts" ever again. What could have driven her into such desperation that she decided to chase a flimsy rumor with such reckless abandon? It is also implied that Saten did all these things without telling Uiharu.
For once, Aisa Himegami might be delighted to be forgotten and not be included in this crossover fan-made game. Her Deep Blood can only be barely kept at bay with the Anglican Church Cross, and without said artifact, it is powerful enough to kill both Scarlet siblings and therefore cause an incident by itself. More so since Himegami hates her power and feels guilty for killing vampires (even in self-defense).
, some "Outsiders" had it rough when they got transported to Gensokyo.