Zappy 2: Series Circuit

How to play

The goal

Electrons are racing from the 9V battery toward Professor Zappy. In Zappy 2 your parts are not towers beside the wire: they are part of the path. Every electron has to go through every part in your circuit. Zappy starts each level with just 1 HP, and each electron that reaches him costs HP (green ones cost 2). Survive every wave to clear the level. There are 50 levels. Level 1 is a guided tutorial that walks you through everything step by step (there’s a Skip tutorial button if you already know how). New things arrive gradually: resistors and blue electrons on level 2, red electrons and capacitors on level 4, green electrons and Zener diodes on level 7 and the fuse on level 11. Every 10th level is a boss level with an extra wave, and the maps get trickier as you go.

1. Build a series circuit, link by link

• One lead per hole. Every hole holds one wire end or one part leg.
• Burnt holes (red X): nothing fits in them, and wires and parts can’t cross them. Later levels use lines of X’s as walls, mazes and chokepoints, so look for the gap.
• Holes a–e in the same numbered column are one connected strip, f–j likewise, and each rail is connected along its whole length. The battery’s lead makes its strip glow: the red + rail at first, other rows on later levels, and Professor Zappy moves around too.
• From any glowing hole (the strip the current has reached) add the next link: either a jumper wire (drag along a row or column, up to 6 holes) or a part.
• Adding a part: pick it in the tray, then tap a glowing hole (or drag it there). Its first leg goes in that hole and its other leg has to land in a new strip, so the current must flow through the part’s body to get there. Press R (or ↻ R) to turn which way it points; a green preview shows where it fits. If both legs were in the same strip the part would be shorted out, so that isn’t allowed.
• Each level limits how many of each part you can use; the message tells you when you hit the limit.
• Keep chaining until a jumper or part lands in Zappy’s strip (purple). Circuit complete! Each strip can only be used once, and you can never join the − rail (that would short the battery).
• ↶ Undo removes the last link, ✖ Clear starts over, and a part’s Take out button removes it and everything after it. All of them give your money back before you press Start. Once the waves start, the circuit is live and can’t be changed.

2. What the parts do (only to electrons inside them)

• Resistor ($10): electrons inside it crawl at 40% speed and lose energy, and come out hot (orange ring), still losing a little energy for 2 seconds.
• Capacitor ($18): charges up by 1 for each electron that passes through (the blue meter). At 4 it discharges: a zap that hurts and stuns every electron close to it, so put it where your wire bends back near itself or right before a Zener.
• Zener diode ($20): blocks electrons (red bar) until the voltage builds up; every waiting electron adds to it (yellow meter). Then it breaks down and lets a burst through, zapping each electron that passes.
• Fuse ($25, from level 11): destroys every electron that goes through it, up to a limit (the bar above it). Then it blows and the circuit is OPEN: electrons pile up at the gap. Tap the fuse to put in a new one ($10). Wait too long (6 seconds of pile-up) and the electrons arc across the gap: the burnt fuse then lets everything through until you replace it.
• Wire: jumper wires have a tiny bit of resistance too, so longer wires drain electrons a little.

3. Money $, hearts and upgrades

Everything is bought with money ($): wire ($1 per hole), parts, upgrades, new fuses and Zappy’s hearts. Each level gives you a budget ($30 in the tutorial and $60 on level 2, rising $5 a level to $295 on level 49, with more on boss levels: $360 on level 50), plus half of the money you had left when you cleared the level before. Retry puts your money back to what you started the level with.

• Earn more by destroying electrons (blue $1, red $2, green $3), clearing a wave ($3) and clearing a level ($10 plus $2 for every HP Zappy has left). You can spend it straight away, even in the middle of a wave.
• Hearts: press +♥ to buy 1 HP for Zappy. The first extra heart costs $4, and each one after that costs $1 more (max 10, then 12 from level 20, and 2 more on boss levels). You can buy hearts before Start and during waves.
• Upgrades: tap a part to see what it does and upgrade it ($8, then $14, then $22, plus $3 for each upgrade already on that part). Resistor: Drag, Power, Heat. Capacitor: Blast (reach), Power, Quick (discharges sooner). Zener: Voltage (holds longer, bigger burst), Power, Drain (waiting electrons lose energy). Fuse: Limit and Slow arc.

4. Start the waves

Press ▶ Start. Blue electrons are the normal kind, red ones are fast but fragile, and green ones are slow, tough and hit harder. ⏩ speeds the game up, and the speaker button mutes it. You can see every part working: resistors glow and steam, capacitors flash a blue shock ring, Zeners show a red barrier and then a yellow burst, and the fuse flashes white each time it eats an electron.

Tip: no parts in the path means nothing stops the electrons. A mix of resistors, a capacitor and a Zener, plus two or three hearts for Zappy, beats spending everything on one thing.

5. 50 levels and saved progress

Levels unlock one at a time. Press Levels ▦ to open the level grid: cleared levels show stars (3 = Zappy never got hit, 2 = hit once or twice, 1 = cleared), and boss levels are marked. Your progress is saved only in this browser, and next time the game continues where you left off. Playing on from one level to the next carries half your leftover money; a level picked from the grid starts with its normal budget.

Your level progress and sound on/off choice are saved only in your own browser (localStorage). Nothing is sent anywhere.

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