Some years ago, I came across a simple Roguelike on Reddit called coreRL. It's very simplistic; levels are just a box with two walls, only one enemy type with basic AI, no health or character attributes, and the only goal is to see how far you can get before you die. Having nothing better to do, I thought it'd be a fun little project to write a port for an Arduino Nano. The only inputs needed are the four movement keys, and the display can just be a basic SSD1306-driven 128x64 OLED panel.
I could, of course, do this in C++. The language is a known quantity for the ATmega328P that powers the Arduino Nano. The toolchain is mature, as are the abstractions for interacting with the onboard peripherals. There are also libraries