MeatSlicer/docs/gameplay.md

Gameplay Guide

Everything about how a run of MeatSlicer: A Butcher's Descent works: the loop, controls, player mechanics, drops, scoring, and difficulty scaling.

See also: Weapons · Items · Perks · Enemies · Bosses

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Core Game Loop

MeatSlicer is an endless arena roguelite. There is no final floor and no victory screen — the goal is to descend as deep as you can and maximize your score before you die. Death is permanent (permadeath); only your high score persists.

A run looks like this:

1. Enter a floor. Each floor is a small map of rooms (see Floor Generation).
2. Clear combat rooms. Doors lock until every wave of enemies in the room is dead.
3. Find the item room. A free passive item (plus a 35% chance of a weapon).
4. Kill the floor boss. The boss room is always the farthest room from the start.
5. Take the loot, take the stairs. Bosses drop an item pedestal, a weapon, guaranteed ammo, and the stairs down. Walk onto the stairs to descend.
6. Repeat, deeper and harder, until you are butchered.

Score

Score is display-only (it buys nothing) and determines your saved best:

Source	Score
Normal enemy kill	+10
Elite enemy kill	+40
Boss kill	+500 (plus drop bonus below)
Boss defeated bonus	500 + floor × 100
Combat room cleared	+50
Descending to next floor	+250
XP gained	+1 per XP (rounded)
Ammo picked up with nothing to refill	+15 (+2 per wasted unit otherwise)
Duplicate item at tier cap (IX)	+150

Your best score is saved in localStorage as meatslicer_best and shown on the title screen and game-over screen ("NEW BEST CUT" when beaten).

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Controls

In-game

Input	Action
W / A / S / D or Arrow keys	Move
Mouse	Aim
Left mouse button (hold)	Fire
Left mouse release	Fire charged beam (Spinal Tap only)
R	Swap between Bone Popper and holstered special weapon
P / Escape	Pause / resume
T	Toggle Auto-Draft (auto-pick random perk on level-up)
M	Mute / unmute
N	Next music track
Shift	Dash in the movement direction; 2× length, 0.6s of 30% slow

Perk draft screen (level-up)

Input	Action
1 / 2 / 3	Choose perk 1, 2, or 3
Click a card	Choose that perk
4 / Space	Random Cut — pick a random perk of the three
R	Reroll the three choices (costs 1 reroll token)
T	Enable Auto-Draft

Pause screen (jukebox)

Input	Action
- / =	SFX volume down / up
, / .	Music volume down / up
; / '	HUD opacity down / up (25%–100%)
[ / ] or Left / Right arrows	Previous / next music track
Click arrows	Cycle music tracks
Drag sliders	SFX / Music / HUD opacity bars are click-and-drag
H / [?] button	Open the 12-page Field Manual

Menus

Input	Action
Enter / Space / Click	Start run (title), restart after death
H / click HD tag	Toggle HD Remaster (title screen; reloads)

The desktop app title screen has [X] Exit to Desktop. Pause has [Q] Main Menu and [X] Exit. The first matching press arms a 3-second confirmation; press it again to confirm. P or Escape resumes. In a web browser, desktop-exit controls are greyed out and non-interactive.

Right-click is disabled (context menu suppressed). There is no interact key — pickups are collected by walking over them.

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The Player

Base stats

Stat	Value
Max HP	6 (shown as 3 hearts, 2 HP per heart)
Hitbox radius	20 px
Move speed	178 px/s (×0.95 while firing the Bone Popper, ×0.85 while firing any other weapon)
Crit chance	5%
Crit damage	×2.0
Post-hit invulnerability	0.9 s
Room-entry protection	1.0 s of invulnerability on entering any room
Starting weapon	Bone Popper (infinite ammo sidearm)
Starting level	1 (0 XP)

Damage, armor, and shields

• Every hit taken deals a minimum of 1 damage (max(1, round(dmg))).
• Armor gives a chance to completely ignore a hit. Each source of armor adds its listed chance directly (e.g. Tanned Hide +8%, Thick Hide +4%) — the block chance is simply armor, capped at 75%. A blocked hit shows "BLOCKED" and grants only 0.2 s of invulnerability.
• Shield hearts (cyan) absorb damage before real HP. They come from the Bone Plate item and Shield Heart perk, and are refilled to full at the start of each floor. Losing your last shield triggers a "SHIELD DOWN" warning. On the HUD they render at half-heart granularity — 2 shield HP = one full cyan heart, matching red hearts (2 HP = 1 heart).
• Getting hit knocks you back 14 px, shakes the screen, and flashes a red vignette.

Healing

• Hearts restore 2 HP (1 heart) each.
• Healing past max HP normally goes to waste — unless you have the Second Stomach item, which converts overflow healing into shield HP. Hearts are not consumed at full HP (they stay on the floor for later, and the magnet won't drag them).
• Other healing sources: Vampire Dentures (kill procs), Hemophage (hit procs), Worm Gut / Bone Knit (post-combat heals).

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Floors & Rooms

Floor generation

• Room count: min(5 + floor, 9) — Floor 1 has 6 rooms, Floor 4 onward always has 9.
• Layout is a random walk from a start room, with ~50% branch chance per step.
• The farthest room from the start becomes the boss room.
• The second-farthest room (distance ≥ 2) becomes the item room.
• Everything else is a combat room. Adjacent rooms are connected by doors.

Room types

Room	Contents	Cleared when…
Start	Nothing	Always cleared
Combat	1–3 waves of enemies	All waves dead
Item	1 item pedestal + 35% chance of a weapon	Immediately (no fight)
Boss	Floor boss	Boss dies

Doors in combat and boss rooms lock until the room is cleared. Re-entering an uncleared room restarts its remaining waves.

The canvas is fixed at 960 × 640. Playable bounds are inset into five room shapes: full hall, wide horizontal hall (224px playable height), tall vertical hall (224px playable width), compact chamber, and inset pit. Start and boss rooms force full halls; item rooms force chambers; combat rooms mix the shapes. There is no camera or larger-than-screen room. Visual tiles recombine into four themes: abattoir, plant, oxide, and flesh.

Waves per combat room

base = 3 + ceil(floor × 1.4)      wave 1: always
floor ≥ 2:  + wave 2 of ceil(base × 0.7)
floor ≥ 4:  + wave 3 of ceil(base × 0.5)

Waves spawn 0.9 s apart, up to a hard cap of 72 simultaneous enemies.

Floor	Wave sizes
1	5
2	6 / 5
3	8 / 6
4	9 / 7 / 5
6	12 / 9 / 6
9	16 / 12 / 8

Combat room rewards

Clearing a combat room drops:

• XP gems worth irand(3, 5 + floor) total
• Ammo at 24% + luck × 30% chance
• Heart at 10% + luck × 30% chance

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Pickups

Pickup	Effect
XP Gem (small, value 1 / big, value 5)	Grants XP × your xpMul. Fills the level bar; each level-up opens the Mutation Draft.
Heart	Heals 2 HP. At full HP: stays on the floor for later (the magnet won't drag it).
Ammo	Refills carried special weapons (current + holstered) by their authored refill × ammoPickupMul × ammoPressureMul() (pressure scaling at 80% of the HP multiplier), up to 150% of magazine size. Overflow becomes score.
Weapon	Equips on walk-over. Your old special weapon drops with its remaining ammo (Bone Popper is never dropped).
Item (on pedestal)	Grants/upgrades a passive item. Hovering near a pedestal shows its name.
Stairs Down	Appears after every boss kill. Walk over to descend.

Pickup behavior

• Magnet radius: 46 × magnet px (46 px base) — gems, hearts, and ammo fly to you.
• Pickups land 0.6 s after spawning before they can be collected.
• Only gems, hearts, and ammo are magnetized; weapons, items, and stairs require walking over them.

Kill drops

Source	Drops
Normal enemy	XP gems (enemy's XP value) · 5.25% + luck×3% ammo · 2.2% + luck×3% heart
Elite enemy	3× XP + 3–5 bonus gems · 18% + luck×10% item · else 45% + luck×15% ammo
Boss	1 item pedestal + 1 weapon (rolled at floor + 2) + 1 guaranteed ammo + stairs · the boss room also stocks 1 ammo when you enter · the stair hatch stays sealed for 3 seconds after the kill

Luck is a player stat (Lucky Coin, Crow Bait, Scavenger perk) that scales most drop chances as shown above.

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Leveling & Mutation Draft

• XP needed for the next level: 8 + level × 4 (level 1→2 needs 12 XP, then 16, 20, 24…).
• Each level-up queues a Mutation Draft: choose 1 of 3 random perks. Multiple queued drafts resolve one after another.
• Rerolls (from the Reroll Rib item) let you re-draw the three choices with R.
• Auto-Draft (T) skips the screen and picks randomly — the setting persists between sessions.

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Pressure (Dynamic Difficulty)

The PRESSURE meter on the HUD is a run-long adaptive difficulty multiplier applied to enemy and boss HP and speed at spawn time. It also multiplies every point of score you earn — the higher the pressure, the more each kill, room, and floor is worth.

• Range: 0.60 – 2.00 (starts at 1.00).
• Gains for rooms cleared without taking damage (flawless streak).
• Taking damage relieves pressure, scaled by how big the hit was, how low your HP is, and how many recent hits you've taken.
• Decays passively while below 35% HP, or if you stall in a room for 90+ seconds.
• Only affects enemies spawned after the change — living enemies keep their stats.

The Pressure Dial

The title screen has a PRESSURE DIAL (−10 … +10) that tunes how pressure responds. It sets two curves — how fast pressure rises per clean room, and how much relief each hit grants (which also scales the passive decay). The midpoint (0) is the standard tuning; the dial persists between sessions.

Dial	Rise / clean room	Relief on hit (base)	Behaviour
−10	−0.020	0.080	Strong mercy; negative rise respects the 0.60 floor
−5	0	0.050	Mercy — pressure does not rise from clean rooms
0	+0.010	0.030	Standard — today's balance
+5	+0.050	0 (none)	Ratchet — pressure can only ever rise; score floored at 1.00×
+10	+0.100	0	Maximum ratchet; pressure respects the 2.00 ceiling

Values between the anchors interpolate linearly. Negative rise respects the 0.60 floor and positive rise respects the 2.00 ceiling. Cranking the dial up is how you chase the BEST CUT.

Streak

The HUD also tracks your streak of consecutive rooms cleared without damage. It is purely cosmetic bragging rights — its only mechanical effect is feeding the pressure gain above.

HD Remaster

An opt-in visual mode toggled from the title screen (press H or click the HD REMASTER tag). When on: the canvas renders at 4× resolution (3840×2560) with smooth scaling, and sprites load from a 4× WebP tier (assets/hd/) generated from the raw source art (assets/raw/) by tools/hd_assets.py — full-color, no palette quantization. The setting persists to localStorage (meatslicer_hd_remaster). Toggling reloads the page (no live hot-swap). If an HD file is missing for a sprite, the loader falls back per-sprite to the standard PNG. Default is off (classic pixelated 960×640 look). The toggle is title-screen only — not in the pause menu (a mid-run reload would lose the run).

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Difficulty Scaling (summary)

Enemy stats scale with floor number, your power score, and pressure:

• Power score = (level − 1) × 0.5 + (sum of all item tiers).
• Enemy HP: base × (1 + 0.22 × (floor−1)) × (1 + 0.05 × power) × pressure (elites ×2.6 more).
• Enemy speed: base × (1 + 0.04 × (floor−1) + 0.01 × power) × pressure (±10% random).
• Enemy contact damage does not scale with floor — only elites get +1.
• Bosses scale the same way but with 30% HP per floor instead of 22%.

Full formulas are in enemies.md and bosses.md.

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HUD Reference

• Top-left — BUTCHER // VITALS: level, hearts (red, 2 HP per heart; half containers render as half outlines) and shield hearts (cyan, 2 shield HP per heart), shown on up to two rows, XP bar, active weapon + ammo (red when below 25%), holstered weapon with [R] swap hint.
• Item tray (below vitals): up to 24 item icons with tier numerals I–IX.
• Top-right — SECTOR MAP: minimap. White = current room, red = boss, gold = item, gray = cleared, maroon = uncleared. Includes floor number.
• Bottom-right — RUN DATA: floor, kills, score (with the live pressure multiplier), PRESSURE % (with the dial setting), STREAK, pressure bar.
• HUD opacity is adjustable from the pause menu (; / ' or the HUD slider, 25%–100%). The boss HP bar and toast notifications always stay fully opaque.
• Bottom-center: boss HP bar (during boss fights).
• Top-center: toast notifications (pickups, floor intros, boss events).

Screens

Screen	What it offers
Title	INITIATE DESCENT, PRESSURE DIAL (−10…+10), HD REMASTER ON/OFF tag, control reference, best score, confirmed desktop exit
Pause	Jukebox (track cycling), SFX/music volume + HUD opacity sliders, resume/swap/auto/mute hints, Field Manual (H / ? button)
Mutation Draft	3 perk cards, random cut, reroll, auto-draft
Game Over ("BUTCHERED")	Floor, kills, score, NEW BEST CUT tag, restart

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Persistence

Stored in localStorage between sessions:

• meatslicer_best — high score
• meatslicer_sfx_volume (default 0.45)
• meatslicer_music_volume (default 0.55)
• meatslicer_autoperk — auto-draft toggle
• meatslicer_pressure_dial — Pressure Dial setting (−10…+10, default 0)
• meatslicer_hud_alpha — HUD opacity (default 1.0)
• meatslicer_hd_remaster — HD Remaster toggle (default off)

Nothing else carries over: no unlocks, no meta-currency, no saved runs. Every descent starts fresh with a Bone Popper and 6 HP.

Death and restart

When HP reaches zero, simulation freezes. Input is locked for 3 seconds, then R, Enter, or a click restarts the run. During the lock the player plays a derived gore animation with particles. Normal damaged monsters show mini HP pips for 2.5 seconds; elite and boss bars stay persistent.