Undertale was groundbreaking in its time. A game that broke the mold, where you had the potential to spare every enemy instead of fighting them. Filled with lovable characters that you may or may not have chosen to massacre depending on the route you were taking, this game also boasted a jarring mix of quirky humor and dark elements. The game is also filled to the brim with secrets, so many that I can’t possibly cover them all. But I’m feeling pretty determined at the moment, so I’ll try to share a few with you guys before I have to go. I can’t put off that plate of Papyrus’ spaghetti forever…
What better time to start than at the beginning, when you’re choosing your own name! There are many different responses to discover, particularly if you try to name yourself after certain characters, such as “nope” for Sans and “I’LL ALLOW IT!!!!” for Papyrus (though it appears Papyru is the closest you can get). As you might have noticed, some characters are more open to sharing their names with you than others. For example, Undyne’s response is “Get your own name!” Alphys, on the other hand, can respond with “Don’t do that”, though you can get away with Alphy, which gets the response of, “Uh…OK?” Catty and Bratty, however, are both totally fine with you using their names, as is Mettaton, who welcomes the use of the name Metta because it promotes his brand. Less…traditional names such as Murder and Mercy are acceptable, too, even if they’re dubbed as “on-the-nose”. Interestingly enough, Chara gets the response “the true name”, while the decision to call yourself Frisk warns you that you’ll get a harder version of the game if you follow through with it. Of course, there are plenty more, and if you want to see the rest, please watch the video below.
Early on in the game, Flowey will try to teach you how the combat works, but if you avoid his “friendliness pellets”, he’ll get rather ticked off at you. You can also wait for Toriel when she has errands to run instead of just proceeding ahead like a naughty child like I did. It can take over 30 minutes to get all the dialogue, but if you’re patient, you can get a call from Toriel saying her chores are taking longer than expected before her phone is then stolen by the Annoying Dog.
In fact, this dog is present for multiple other secrets found throughout the game. For example, the Dog Shrine is a secret exclusive to the PS4 version and can be found beneath Papyrus’ kitchen sink. It is here that you can donate money so that the dog can buy useless stuff with it, such as those creepy inflatable things they put outside car dealerships. As far as I remember, this was mainly a silly way to earn trophies. There’s also a mysterious door outside of Snowdin that can only be unlocked by completing a True Pacifist Run and dodging all the names in the Special Thanks section of the credits, which is an incredibly difficult thing to do. And on the other side of said door is…a sleeping dog? Huh, I’m sure that was worth the effort…
And let’s not forget an entirely different dog, the Lesser Dog, whose neck will continue to get longer and longer and longer the more times you pet it!

Temmie Village is another secret that can be found by taking a hidden path in Waterfall. It is inhabited, as expected, by Temmies, which are these cat/dog-like creatures with rather low intelligence that like to greet you with, “Hoi! I’m Temmie!” One is even waiting for a hard-boiled egg to hatch…. Aside from just being a generally silly place, I think this is the only place where you can sell your items. Plus, you can also send the shopkeeper Temmie to college, which grants it the ability to sell you Temmie Armor.
Lastly, I just wanted to briefly touch upon one of the greatest mysteries of Undertale, WD Gaster, an enigmatic character whom I’ve already talked about in this here post. Basically, he was once the Royal Scientist before Alphys, but was erased from existence. And yet, in extremely rare instances, you can still find him and his followers, and there is even an entry in the True Lab that was most likely written by him. For me, this is one of the most intriguing mysteries in gaming, and I have to wonder if it will ever be solved….

Honestly, Undertale is so packed with secrets and hidden interactions and whatnot that I’ve barely scratched the surface. (I didn’t even mention the dialogue you get from calling Papyrus from different rooms!) From unsolved mysteries to secret locations to dialogue most people will miss even after multiple playthroughs, perhaps this is one of the many reasons Undertale won’t ever be forgotten. Any game that allows you to keep discovering new things on each subsequent playthrough has got to fill anyone with determination!