Zero Tolerance screenshot

Release year: 1994

Zero Tolerance

Category: ActionTactical Shooter

The year is some unspecified future and the space station Europa-1 is already on fire. Strange creatures move through the smoke. The few humans still breathing won't be for long. The Planet Defense Corps calls in Zero Tolerance — five commandos with different specialties and one shared problem: hours before the nuclear core blows.

That setup drives a first-person shooter unlike most things on the Genesis/Mega Drive. Zero Tolerance put a genuine FPS on the system in 1994 — one of very few FPS games the base Genesis ever got — with 40 levels spread across a burning space station, a besieged skyscraper, and a maze of sub-basement corridors. The 3D view is constrained to roughly a fifth of the screen, surrounded by HUD, and the turning speed is sluggish enough that you'll be strafing more than you're spinning. The framerate sometimes tanks. None of that stops the game from working.

Your team of five can be depleted and each death is permanent — lose them all and it's over. Which character you pick matters: Satoe Ishii absorbs gunfire until her vest runs out, Tony Ramos starts with no weapons at all but can one-shot enemies with his fists, and Justin Wolf gets 25 HP out of every medipack instead of the usual 20. Small edges that compound across 40 levels — see which one carries you further when you play Zero Tolerance online right here.

Start
Start / Pause in game
Joystick
Movement
A
Special movement
B
Fire
C
Toggle items
Save / Restart / Load

Animated Screenshots

Zero Tolerance title screen on SEGA Genesis/Mega Drive
Zero Tolerance — Reactor 1 level gameplay on SEGA Genesis/Mega Drive
Zero Tolerance — High Rise Floor 155 level gameplay on SEGA Genesis/Mega Drive
Zero Tolerance — Sub-Basement 7 level gameplay on SEGA Genesis/Mega Drive

Controls

On PC you move with the keyboard; on mobile it's the joystick. Fire with K, cycle through inventory with L. That part is simple. Button Space is the awkward one: it's a modifier that changes with direction: Space+ jumps, Space+ ducks, Space+ or Space+ sidesteps.

Strafing is how you survive firefights, so learn it before things get crowded. When something moves in a doorway ahead of you, pivoting to face it takes too long. Stepping sideways while keeping your aim steady doesn't. That's the whole game in a sentence.

Two things trip people up early. There's a brief acceleration phase before you hit full speed, so tapping forward and expecting instant movement will cost you. And when you take hits the character lurches and the screen shakes — it reads like loss of control, but it passes fast. Keep moving.

Passwords

One thing to know before relying on these: the game only gives you a password after you finish an entire area, not individual levels. There's no mid-High Rise save point. If you want to resume from Floor 157, you need to have already cleared everything above it and earned the code. That said, having the full list here means you can jump straight to wherever you left off — or skip ahead to a section you haven't reached yet.

The boss codes are the ones most worth bookmarking. Each starts you at the boss fight with 90+ Pulse Laser Rifles already in hand. Against all three bosses, the approach is the same: stay at distance and hold the fire button. The Pulse Laser barely misses at range, and none of the bosses close fast enough to punish you for it.

Zero Tolerance — password entry screen

Available passwords

Space Station

  • Docking Bay 2: bnp8vt)ng
  • Bridge 1: DDq8vNLng
  • Engineering 1: HFr8*tLng
  • Engineering 2: HHoduvNng
  • Engineering 3: ?rvd-vPn4
  • Engineering 4: bDq*-vOvT
  • Green House 1: V86*CrP!2
  • Green House 2: GLq*-vPv2
  • Green House 3: ?r)*u*rrk
  • Bridge 2: TPu8uvLgK
  • Reactor 1: PFr*-vKqx
  • Reactor 2: HDq*-vKqx

High Rise

  • High Rise Top: NUq8uPKgR
  • High Rise Floor 164: Rzr5uPxvM
  • High Rise Floor 163: aHqXuvDmE
  • High Rise Floor 162: OvK7C8?vK
  • High Rise Floor 161: GLo7CrHv!
  • High Rise Floor 160: ?rpQsrHv7
  • High Rise Floor 159: TLFX/oxkQ
  • High Rise Floor 158: E*hUt)Bk7
  • High Rise Floor 157: cLtXtox!7
  • High Rise Floor 156: Tr)5--Dr!
  • High Rise Floor 155: ?Pr5--Dr!
  • High Rise Floor 154: GrozCoHpj
  • High Rise Floor 153: GLpUsoHhj
  • High Rise Floor 152: ?ro5--?FQ
  • High Rise Floor 151: TLFXCoxo7

Sub-Basement

  • Sub Basement 1: MLFXtxBh/
  • Sub Basement 2: Tr)*4-?n!
  • Sub Basement 3: TLp*7o?tk
  • Sub Basement 4: crod!o?sE
  • Sub Basement 5: cLJ*4-?vj
  • Sub Basement 6: Dnpdmu)v5
  • Sub Basement 7: KLLbm-NmQ
  • Sub Basement 8: Orrf!oN!7
  • Sub Basement 9: WLRd2a)kQ
  • Sub Basement 10: 8b*2APo!
  • Sub Basement 11: KLa*w60ip
  • Sub Basement 12: Gn9by6Npt

Boss codes — 90+ Pulse Laser Rifles pre-loaded

  • Boss 1 (Reactor Level 2): cP98CrOFK
  • High Rise Rooftop (stuck on the boss): PP6b-rNpV
  • Boss 2 (High Rise Floor 151): aLo5-vxF2
  • Sub Basement Level 1 (stuck on the boss): GDq56PxF3
  • Boss 3 (Sub Basement Level 12): Pvbd76Noj

These are the codes that matter most if you want to see the boss fights without grinding through all 40 levels first.

Engineering elevators

The Engineering section of Europa-1 is where most first-time players get completely stuck — not from enemies, but from the elevators. The connections between levels don't follow any obvious logic, and the game gives you no hint that they don't.

The short version: Engineering Level 1's elevator skips Level 2 entirely and takes you to Level 3. If you take it expecting to go to Level 2 in sequence, you'll never arrive. Level 2 requires a detour.

To reach Engineering Level 2, you first need to get to Level 3. From there, take the elevator at the 9 o'clock position. It will carry you toward Level 4 — wait for the music to change, then step off. You're now on Level 4. Reboard the same elevator and ride it back up. It stops at Level 2.

Two more things worth knowing while you're in this section. Engineering Level 2's elevator goes to Level 4, but if you want Level 3, exit manually when the music shifts during the ride. Level 3's elevator circles back to Level 2; step off when the music changes, then reboard to reach Level 4. The music cue is the only reliable signal the game gives you — when it shifts, you've crossed into the next level's territory whether or not a door has opened in front of you.

Inventory crunch

Five slots. No drops. That's the whole system, and it's tight enough that you'll feel it before you're halfway through the Space Station. Whatever you're carrying in slot 3 (the middle position) is what fires when you press K. Cycling with L rotates the whole stack, so rearranging means tapping through until the thing you want lands in the center.

The problem arrives when something you actually need — a fire extinguisher, a medipack, a bullet proof vest — is sitting on the floor and all five slots are occupied. There's no context menu, no discard option. To make room, you shoot. Fire your handgun dry, burn through a stack of shotgun shells, throw grenades until they're gone. It feels wasteful because it is. On the later High Rise floors where fires block entire corridors, showing up without a fire extinguisher or fire suit is worse than showing up with slightly fewer rounds, so the math usually works out. But unloading ammunition into a wall just to free a slot is genuinely uncomfortable the first few times it happens.

One pattern worth building early: keep slot 1 or 5 as your "expendable" position, the slot you fill with whatever you're about to use up or trade out. Medipacks burn in one use; grenades and mines go fast. If your disposable items are always at one end of the stack, you'll cycle less and waste less time repositioning mid-fight. It doesn't make the five-slot limit generous. It just makes it livable. Play Zero Tolerance online and see how far your inventory management takes you.