Oh my goddddd, I absolutely love reading through this IF!! It really brought me back to my phase and I absolutely adore how the world of Underfell is. While Underfell is primarily known for its violence, I think many forget that at its core, it's just a world filled with people who desperately needs kindness in their lives. I'm one of the people who forgot that core mechanic but since going through this IF I've rekindled that thought process. I love how, despite dying, our MC (Frisk) still does their best to look on the bright side and continuously spares monsters (depending on the choices). I also love the interaction of different monsters (ngl, I love the interactions with Shyren) and the bond between Flowey and MC (Frisk) is very wholesome.
The run in with Toriel was sad but hopeful, I really love how we could give a hug to her because the poor woman desperately needs it. The entire run in with Papyrus was just heartbreaking, especially with his dialogue to each time you die. And the run in with Undyne was tense and while it didn't feel neverending like Papyrus, I love how the two's goals aligned at the very end of the fight: They didn't want anyone else to get hurt aside from each other.
But more so, I love the little interactions we have with the side characters and learning about them while balancing through the tightrope that is life and death. Looking forward to the progression of the IF and meeting more people!!