From a pocket 15 Tiles to four games on one Nano

In March 2025 I wrote about a portable 15 Tile Puzzle: directional buttons, a small display, USB-C charging, and a rechargeable battery. The goal was a self-contained sliding puzzle you could carry without plugging into a computer.

That build answered a simple question: can the classic puzzle feel good as a small electronic device? The later work answered a harder one. Once the controls, display, and shuffle logic were solid, what else could share the same hardware without turning the firmware into a mess?

The Arduino Nano collection that followed keeps 15 Tiles as the foundation and adds Snake, Neo Fleet, and Nu Pogodi on one 240 × 240 ST7789 display and one joystick. Version 1.4.7 uses about 96% of the Nano’s flash. Static RAM stays modest so the stack still has room, but the remaining flash is not spare capacity for casual features. Every new screen, sprite, or game rule has to earn its bytes.

A few constraints shaped the collection more than any feature list:

• Keep the measured joystick wiring. On this board, up and right lower the analog channels, so “correct looking” controls that ignore the measured directions feel broken in the hand.
• Redraw only what changed. Menu selection updates outlines; Snake redraws affected cells; Nu Pogodi leaves static farm scenery alone while eggs and the wolf move.
• Reuse art in flash. The Nu Pogodi menu portrait is cropped from the same run-length-encoded character data used in-game.
• Exit reliably. A one-second Select hold returns to the menu from any game, so you do not need a separate back button on every screen.

The older portable write-up was a product sketch. The Nano series is the engineering record: solvable shuffles, turn timing, opponent targeting that follows hits rather than cheating with hidden ship maps, and staged rendered states so every screen can be reviewed at native resolution.

I still like the pocket puzzle idea. USB-C power and a dedicated button layout are a different product from a joystick Nano. What the four-game firmware proves is that the interesting limit is rarely “can I add one more game.” It is whether the next idea fits the flash budget, the redraw rules, and the same physical controls without making the earlier games worse.

If you want the full tour of menus and all 28 rendered states, the detailed Arduino post covers the current build. This note is the short path between the first portable 15 Tiles and the collection it became.