Review of CALVIN Core, a chaotic game of creative system building!

CAVLIN Core is a tabletop RPG system that lets you change the rules!  Starting out simple and getting more complex as you go, it makes for some very interesting and very fun game sessions! 

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CALVIN Core is great for all-ages

Calvin Core is a game system, so you and your players create the setting and figure out where you’ll go, so you can make the tone and themes fit your players.

For math and reading, the mechanics start out with just a 1d6 roll and no modifiers and then grow more complex as you and your players direct them to as you go, so you can adjust your rule changes to match your player’s needs as well.  If you want to practice math, you can add in more rules based around adding modifiers.  If you want to stay away from more complex math for your particular players, you can direct rule modifications towards different avenues (more on this later). 

There’s also not a lot of reading involved except to keep track of your new rules on a sheet so you don’t get lost while adding things.  You can adjust the complexity of this reading or help players by practicing the rules as you go (which the game naturally sets you up for) so they can remember them without needing to read the sheet. 

CALVIN Core can be set anywhere!

CALVIN Core is a genre agnostic setting, so you can set it anywhere you want!  For our game, kiddo chose to go to a Halloween planet and had a cat character with Spider-Man powers, and the system worked GREAT despite that particular setting and combo being very creative.

Player characters in CALVIN Core

CALVIN Core focuses on the mechanics side of things and doesn’t require you to set up player characters, unless you want to. Characters can be in your head as a basic concept (like kiddo’s Spider-Cat character) or you can draw them out, write the story up, etc.  You have freedom to go as abstract or complex as you want.

Mechanics in CALVIN Core

Only Three Rules

CALVIN Core has three rules that hold the system together… and create more rules. 

First, you roll one die to meet a certain criteria, and if you meet that criteria, you succeed.  This is your base rule that you’ll build everything else from (or can change entirely). 

Second, if you succeed, you get to create a new rule!!!

Third, the new rule has to be respectful to others.

And that’s it!!  

These were REALLY easy to explain to my kid, the third rule helped to keep things bounded, and despite it being a simple explanation, it creates SO MUCH for the game.  Because you can change the rules, especially in a game with kids, it starts to get wild… 

Constantly Altering Law-Variation and Innovative Nonsense

And now to the name of the game itself!  CALVIN stands for Constantly Altering Law-Variation and Innovative Nonsense because of that rule changing mechanic, and this got really fun. 

When we first started out, we were just rolling our 1d6, and then success after success, we ended up with new rules like: 

  • +1 to your roll if you make a Spider-Man web shooter hand motion
  • -2 to your roll (and wash the die) if you pick your nose (YUCK!)
  • Run three laps around the house if you get a fail
  • For casting a spell, roll 2d6 and then take the lowest result
  • Casting a spell requires you to wave your arms around and yell out the name of the spell or it won’t work!

After about 12 turns, we had a pretty interesting and engaging game going, and my kid was super into it because they got to help create it!  

I also really like how the new complications are introduced gradually so my kid had the chance to get used to the new rule before another one was added.  It builds in sequentially introducing mechanics, and, because half the rules that we made were my kid’s idea, they REALLY remembered them.

Overall thoughts on CALVIN Core

We had a lot of fun with this system!  It’s the right level for my kid to understand the basics, and it gets complex enough to stay interesting over the course of a long game.  This system also promotes creativity and helps lay the foundation for game design as you come up with a ton of different mechanics and see how they play off of each other.  We really enjoyed this short but awesome system, and I hope you get the chance to check it out too!

Find a copy of CALVIN Core

You can find a copy of Calvin Core here on DriveThruRPG!

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