Game Design #20: Penicillin
Introduction: Grow and devour — this is your calling. In Penicillin, players take on the role of a bacteria culture, spreading with relentless, single-minded purpose to overrun their opponents and consume the board before those pesky antibodies can catch up to them.
Players: 2+
Materials:
- Pens or markers of different colors, one per player.
- One sheet of standard, letter-sized (A4) paper.
- A penny, for size comparison.
Setting Up: Lay the sheet in the center of the table and distribute the pens or markers to each player. Players take turns drawing circles on the paper, each approximately the size of a penny, with a small hash mark on their circumference — these are their starting hot spots (see below). Players may draw circles anywhere they wish as long as no circle overlaps another circle or the edge of the paper; continue until each player has drawn six circles. Designate a first player; play proceeds to the left.
How to Play: Players act in turn to grow their territory out from the circles they drew during setup, seeking to devour the growth of their opponents before antibodies consume their forces. Each circle drawn during setup represents a bacteria culture, called a hot spot. On their turn, players may make a single free action to either strengthen a hot spot, grow their culture, or attack their opponents. Once their free action is complete, players may take any number of further actions by opening their cultures to attack by antibodies (see below). Once a player has finished taking actions, their turn ends. The actions available to them are as follows:
- Strengthening Hot Spots: Strengthening hot spots means adding striking power. Each hot spot can be strengthened a maximum of five times. To strengthen a hot spot, players draw a feeler — a small hash mark extending from the circle (players are encouraged to keep the hash marks short, to keep the board from becoming cluttered and confusing). Feelers are used to make connections to other hot spots in order to grow the culture or attack opponents’ hot spots.
- Growing the Culture: Culture means influence. To expand the culture, the player draws lines between their existing hot spots. These lines must be straight, they must touch exactly two hot spots (not counting opponents’ hot spots), and the two hot spots being connected must both have an available feeler — each connection is made between two feelers, and each feeler can support only one connection (thus, each hot spot can support a maximum of five connections). Connections are made to form triangles of three hot spots and three lines. Whenever a triangle is formed (i.e. on the turn the player draws the third side) the player may immediately add a new hot spot with a single feeler anywhere inside the triangle’s area. The new hot spot must conform to the size and placement constraints as those made during setup — if there is not enough room to add a new hot spot inside the triangle, none may be drawn. Otherwise, the new hot spot will be available to be strengthened and used for growth or attack on the player’s next turn.
- Attacking Opponents: Players eliminate each other by eliminating hot spots. In the same manner as growing the culture, players draw lines to form triangles around their opponent’s hot spots. On the turn the triangle is formed, the player draws a line through the enclosed hot spots — enclosing multiple hot spots is allowed, and the player may draw lines through every hot spot they surround. Hot spots do not need to be fully enclosed to be damaged — as long as the triangle either surrounds or intersects the hot spot, it is susceptible to the attack. Each hot spot can take one hit before it dies: if the player attacks hot spots that already have been damaged (they already have one line drawn across them) they draw a second line to form an ‘X’, signifying that the hot spot is dead. Dead hot spots may not be used to form connections and are worth no points.
Antibodies: To take extra actions, a player marks their own hot spots with lines exactly as if they had been damaged by an opponent. For every damage mark they make, they may make a single further action. Note: damage does not need to be applied to the hot spot the player wishes to act on. They may damage any hot spot they control in order to take an action anywhere on the board. Players may kill their own hot spots in this way.
Winning the Game: Play continues until no more actions are possible for any player. For every live hot spot a player controls at the end of the game, they score one point. The player with the highest score wins.
Next: Designing “Penicillin”:
This game was a hard one to make. While I think the idea is interesting, I am uncertain about the specific execution. With my choice to attempt to move away from playing cards, I’ve left myself in a bit of a pickle — the range of options for playing pieces and surfaces are very limited if your goal is to make a game that fits onto one page and can be played with no custom components and minimal setup. It forces me to design from technical constraints — a position many experienced designers believe to be the worst way to design. Nevertheless, I have no choice if I want to avoid designing a new set of playing pieces every week. Until something better occurs to me, this is what I have to work with.
The key mechanic in this game is preparatory sacrifice. By planning ahead, the player adds feelers to hot spots they know will be crucial later, and timing the “antibody moves” such that the cost is outweighed by the gain in destroyed opposing spots. I can envision situations where a player keeps a few hot spots in reserve in the corner where they cannot be reached, waiting to be sacrificed to gain a single-turn thrust that could wipe out multiple enemy spots.
As with my earlier draw-the-board games, I’m worried that the need to rely on players being reasonably honest about what constitutes “straight lines” or “the size of a penny” opens the game to everything from inadvertent cheating to callous exploitation. If the game were made with pre-made components, or in a digital format where the size and placement could be controlled by the computer, I think it would be much safer. I have a suspicion that, if I playtest this game, I will run into enough technical hurdles that it will difficult or impossible to critique the system. However, I maintain that I think I have a good idea here, and I will do my best to see if I can put it to the test. Of course, if any readers wish to do so on their own I would be overjoyed to hear the results ![]()
This sounds like a fun game with interesting choices. Maybe I can wrangle someone into playing it with me.
A couple of comments on the rules writeup:
- “as long as the triangle either surrounds or intersects the triangle” I assume you mean “hotspot” for that second “triangle.”
- “can sustain two attacks” To me, this sounds like it can still be alive after two attacks. You make it pretty clear immediately following that when there is an X over the hotspot, it’s dead, so this is a minor point, but it could probably be made slightly clearer.
Good points, thank you. I’ll modify the post for clarity.
I hope you do get to play it! I want to know how it works.
I’ll just say, these posts cry out for example game pictures.