First, I can tell this is a spiritual successor to Night of the Stars. But one could say this game is also the complete opposite of NOTS in everything it stands for.
Between Callaghan and Luke, Luke is level-headed and optimistic, taking the time to help people along with doing his quest. The danger was already well-known, he trained himself all throughout his life to confront the danger and he never lost sight of himself or his goals. Even against unsavory foes, he never abandoned his ideals and remained true to his beliefs.
Callaghan is the exact opposite of Luke. He's older, cynical and more importantly: pragmatic. He's not hesitant to get his hands dirty, throw anyone in his way to the wolves and is more single-minded in his obsession to rescue Carla. He'll do whatever it takes to achieve his goals, even if it means ruining innocent lives along the way.
The party members are also different. Night of the Stars has essentially demigods who already faced the dangers before. When Luke gains their approval, they join him and tell him more of the dangers. They have time and experience to make smart decisions. Odessa has the party scrambling to find even a shred of answer to find their destination. Everything is spontaneous with hastily-made plans and trying to figure out what works in such a short time frame. In fact, Rose joining Callaghan was necessary to keep him in check rather than him treating her as an unwanted partner. If she wasn't there, the journey would have ended much sooner with Callaghan's loss.
After the danger was defeated, NOTS had everything end on a happy note, regardless of what Luke chose. This game... not so much:
Spoiler: show
This game is overall a good experience. It's a complete 180 from Night of the Stars. Props to the creator for good storytelling and battles.
Lastly... Monster Touhou battlers? Really? That was unexpected.
