The game Deltarune is quite an impressive one comparing to some games I have played. Interesting story, interesting characters (plot twist and a character easter egg is there) and a fun game mechanic.
If you have played undertale, you know at least 65% of the entire characters. If you have played touhou, you know the game mechanic. Although it is not entirely touhou, it has the bullet dodging feature. Otherwise it is a turn based game.
The outcome of the game won't be changed in a huge scale by your actions as in undertale, but there are some things that you can focus on. Try in different play-styles and see the endings by yourself.
I personally like the entire series, and one thing that you must remember is that everything in this game depends on your actions. Play the game while keeping that in mind.