Boost Mettaton EX's Ratings...
	Developers' Room...
	Easily Defeat Muffet...
	Various Trophies...
	Weaken Asgore...

During the final fight with Mettaton EX, if you have certain fashionable items, such as the Stained Apron or the Cloudy Eyeglasses, your ratings by default are boosted. Furthermore, certain items being used, such as the Glamburger, will boost ratings. This will make it easier to end the fight sooner.

In Snowdin, there is a large door that normally doesn't open for you, To open it, complete the credits without touching a single name, and beyond you'll find the developers' room.

To defeat Muffet in a single turn, you can use one of the Spider Bakery items - the Spider Donut and Spider Cider - you can buy significantly earlier in the game. Use one during the fight and it'll end immediately.

Complete the following tasks to unlock PlayStation 4 trophy rewards.

Trophy	How to unlock	Type
Dognation Level 1 (secret)	Donate 2G to the Dog Shrine.	Bronze
Dognation Level 10 (secret)	Donate 125G to the Dog Shrine.	Silver
Dognation Level 11 (secret)	Donate 155G to the Dog Shrine.	Silver
Dognation Level 12 (secret)	Donate 190G to the Dog Shrine.	Silver
Dognation Level 13 (secret)	Donate 230G to the Dog Shrine.	Gold
Dognation Level 14 (secret)	Donate 280G to the Dog Shrine.	Gold
Dognation Level 15 (secret)	Donate 350G to the Dog Shrine.	Gold
Dognation Level 2 (secret)	Donate 6G to the Dog Shrine.	Bronze
Dognation Level 3 (secret)	Donate 12G to the Dog Shrine.	Bronze
Dognation Level 4 (secret)	Donate 20G to the Dog Shrine.	Bronze
Dognation Level 5 (secret)	Donate 30G to the Dog Shrine.	Bronze
Dognation Level 6 (secret)	Donate 43G to the Dog Shrine.	Bronze
Dognation Level 7 (secret)	Donate 59G to the Dog Shrine.	Bronze
Dognation Level 8 (secret)	Donate 78G to the Dog Shrine.	Bronze
Dognation Level 9 (secret)	Donate 100G to the Dog Shrine.	Silver
Don't Worry, I Have Lots of Ideas for Trophies (secret)	Get an item.	Bronze
Don't You Have Anything Better to Do?	Obtain all other Undertale trophies.	Platinum
Exodus (secret)	Arrive at Snowdin.	Bronze
Final Stretch (secret)	Enter Hotland.	Silver
Final Stretch II (secret)	Reach Hotland 3F.	Gold
Final Stretch II (secret)	Reach Hotland 2F.	Silver
Good Luck (secret)	Reach the second save point in the CORE.	Gold
Help Me, I'm Out of Ideas (secret)	Get four items.	Silver
Like Getting Items (secret)	Get two items.	Bronze
Manna (secret)	Get to the Spaghetti save point in Snowdin.	Silver
Midpoint (secret)	Arrive at Waterfall.	Silver
Mouse (secret)	Reach the mouse hole in the Ruins.	Bronze
Or Getting More Items (secret)	Get three items.	Bronze
Rain (secret)	Reach the place where it rains.	Silver
Ruins (secret)	Enter the Ruins.	Bronze

If you save the pie given to you by Toriel from the beginning of the game, and use it during the final battle versus Asgore, you will weaken his attacks noticeably; being relatively hard to dodge, this makes the battle significantly easier.