Undertale is a 2D deliberately-retro fantasy RPG developed and published digitally by tobyfox for PC, Mac, and Linux on September 15, 2015. It was later digitally ported to the PlayStation 4 and PlayStation Vita by 8-4 on August 15, 2017.
Billed as an RPG in which enemies can be defeated non-lethally, players control a mysterious silent human child who falls into the Underground: a hidden realm of monsters magically sealed away from the surface world long ago. After acclimating to their new surroundings, the child must find a way to return to the surface. The game employs a unique turn-based combat system combining elements of bullet hell shooters with traditional menu-based commands. NPCs react differently to the player character depending upon their moral choices during the course of the game, leading to one of several possible endings.
Players navigate the retro-stylized 2D world of Undertale from a top-down oblique perspective. Like most RPGs, Undertale's silent protagonist will interact with many non-player characters through dialog text boxes over the course of the game. Many areas also feature random encounters with monsters. Undertale primarily uses the framework of a traditional turn-based RPG combat system to present its encounters. The main battle menu displays four basic commands: "FIGHT," "ACT," "ITEM" and "MERCY".
- FIGHT: The player physically attacks a monster with their equipped weapon. After choosing "FIGHT" and selecting a target, a slider bar appears on-screen, allowing the player to perform an active reload-style quick time event to determine the amount of damage dealt. Monsters may also attempt to dodge the attack. Like the player, monsters die when their HP reaches zero.
- ACT: The player interacts with a monster in a non-violent fashion. Selecting "ACT" and a corresponding target will open a sub-menu with one or more possible actions, which vary depending upon the targeted monster. Undertale features a variety of unusual ACT commands such as "pet," "encourage" and "tell joke"; by choosing the correct sequence of actions, the monster's name will turn yellow in battle menus, indicating that the monster is reluctant to continue fighting.
- ITEM: Opens the player's inventory to select a single item for use during their turn. The player can also equip armor or weapons during battle through this menu. Some items can end certain battles non-violently on their own.
- MERCY: The player attempts to resolve an encounter peacefully. Choosing "MERCY" allows players to either "Spare" monsters or attempt to "Flee". Monsters can typically be Spared only after the player has ACTed one or more times to make the monster friendlier as indicated by their yellow name. Certain monsters can be Spared immediately without the need to ACT. Other monsters, particularly bosses, may require players to repeatedly Spare them in order to reach a peaceful resolution.
The player acts first in nearly all encounters. After the player's turn, any remaining monsters will attack the player simultaneously in a bullet hell-style micro game. The protagonist's "SOUL," represented by a heart, appears inside a white "bullet box" near the middle of the screen during the enemy's turn. The SOUL is maneuvered with directional keys, allowing players to dodge enemy attacks and avoid taking damage.
Enemy attacks are color-coded by their effect. Most enemies attack using white-colored objects, which damage the player's SOUL upon contact. Green objects will actually heal the player. Additionally, some enemies can only be Spared after the player has touched one or more of their green projectiles. Aqua-colored attacks only deal damage if the player's SOUL is in motion; conversely, orange attacks deal damage if the player's SOUL is stationary.
Most of Undertale's boss fights include special "soul modes" that significantly alter the manner in which the player's SOUL behaves while inside the bullet box.
- Red: The default color. While red, a player's SOUL can freely move anywhere within the borders of the bullet box. This is the only mode in which players may attempt to Flee from an encounter.
- Blue: The SOUL is affected by gravity and must avoid obstacles by jumping with the Up directional key in a manner similar to an auto-scrolling platformer.
- Green: The SOUL is immobilized and uses a shield to deflect incoming magic spears. Using the arrow keys, the player positions their shield as each spear approaches from one of the four cardinal directions.
- Purple: Horizontal lines appear in the bullet box, and the enemy projectiles will follow these lines. The player's SOUL may only move left or right along the lines, but it can switch to a new line with the up or down keys.
- Yellow: The yellow SOUL is flipped upside-down and can fire bullets from its tip, which can destroy certain incoming enemy projectiles or damage enemy characters directly.
Undertale's original soundtrack was composed by Toby Fox and is available on his bandcamp page (some songs are hidden).
Once Upon a Time
Your Best Friend
Uwa!! So Temperate♫
Home (Music Box)
Nyeh Heh Heh!
Uwa!! So Holiday♫
Bird That Carries You Over A Disproportionately Small Gap
Spear of Justice
Uwa!! So HEATS!!♫
Can You Really Call This A Hotel, I Didn't Receive A Mint On My Pillow Or Anything
Wrong Enemy !?
Oh! One True Love
It's Raining Somewhere Else
Death by Glamour
For The Fans
Song That Might Play When You Fight Sans
Your Best Nightmare
She's Playing Piano
Here We Are
Fallen Down (Reprise)
Don't Give Up
Hopes and Dreams
Burn in Despair!
SAVE the World
Bring It In, Guys!
But the Earth Refused to Die
Battle Against a True Hero
Power of "NEO"