My submission for the jam is not a game, but an engine I made in BlitzMax. The main attraction is the entity component system.

https://github.com/fightlessbirds/rcge

-Entities are basically a unique ID with some related components.
-Components are an object with fields.
-Systems are chunks of logic.

The ECS allows one to dynamically build entities at runtime, adding and removing components at will. Systems will only process entities with components they are concerned about.

While working on this I took inspiration from some existing ECS implementations: artemax.mod (BlitzMax), Ashley (Java),  crafty.js, esper (Python)

Here is a nice article explaining what an ECS is and what its advantages are.