Everything you need to know in one read — controls, enemies, levels, scoring, and the airplane that flies you between cities.
You play as a coronavirus on a global tour. Your job is to grow as long as possible by infecting cells, while avoiding the immune system: vaccines, antibodies, and quarantine zones. Each time you exit one edge of the play field, you board an airplane and fly to the next city. Survive long enough and you'll cycle through all seven destinations.
The game ends when a vaccine takes your last segment, when an antibody knocks you down to nothing, when you ram into a quarantine wall, or when you bite your own tail. Your highest score is saved in your browser between sessions, so the game remembers your record even after you close the tab.
| Action | Keys |
|---|---|
| Move up | W or ↑ |
| Move down | S or ↓ |
| Move left | A or ← |
| Move right | D or → |
| Start / restart | Space or Enter |
| Pause / resume | P or Esc |
| Return to main menu | R (after game over) |
Swipe in any of the four cardinal directions on the play field to change heading. A short, decisive swipe of about 20 pixels in either axis is enough to register. Tap the canvas once to start a new game from the main menu or after a game over.
You are the spiky red blob with cartoon eyes. The head leads, and a chain of slightly smaller, semi-transparent body segments trails behind. The longer you grow, the harder it is to maneuver — but also the more impressive your score becomes. Snake-style self-collision applies to anything beyond the fourth segment, so the first few segments behind your head will not kill you.
Two kinds of cells appear on the grid:
The grid keeps a minimum of three cells alive at any moment. As soon as you eat one, another spawns somewhere safe.
Vaccine syringes fly across the screen from random edges with semi-random heading. They appear more often as your level rises. If a vaccine touches your head, you instantly lose six segments. If it touches your body, you lose two. Either way, the vaccine is consumed on impact, and the screen flashes blue with a brief shake. If a vaccine reduces you to a single segment, the game ends.
Starting at level 4, drifting Y-shaped antibodies appear and bounce off the edges of the play field. They move slowly but unpredictably. A collision costs you three segments and is consumed on impact, just like a vaccine.
Starting at level 3, yellow-and-black hazard tiles fade into existence on random empty cells. They're stationary, but if your head enters a fully-formed wall, the game ends instantly. Walls take a moment to materialize, so a tile that just appeared is briefly safe to cross — but only briefly.
The play grid does not have hard walls. When you exit any edge, your snake's head wraps around to the opposite side — but the entire scene also changes. The play field freezes for a brief animation: an airplane flies across the screen, a banner reads "FLYING TO <CITY NAME>", and the backdrop swaps to a new skyline. You'll cycle in this order:
New York → Paris → London → San Francisco → Tokyo → Dubai → Hong Kong → New York → …
The airplane animation is purely cosmetic. Cells, vaccines, antibodies and walls all keep doing what they were doing before the flight. There is no penalty for traveling — and no bonus, either. It's a gift to your eyes.
Every 120 points of score earned, you advance one level. Each level does three things:
The HUD strip in the upper-left corner of the play field shows your current level as a row of pixel bars. When the bar fills up, the level just changed and the screen flashes briefly yellow.
| Event | Effect |
|---|---|
| Eat a normal cell | +10 points, +1 segment |
| Eat a super cell | +50 points, +1 segment |
| Vaccine hits head | −6 segments |
| Vaccine hits body | −2 segments |
| Antibody collision | −3 segments |
| Quarantine wall touch | Game over |
| Self collision | Game over |
| Reach 120 × N points | Level N + 1 |
Knowing the rules is one thing. Surviving past level 5 is another. Head over to the Strategy guide for the tactics that turn a thirty-second run into a five-minute one. Or read more about how the game came together on the About page.