Shovel Knight: King of Cards

Borrow from a whole era so you never compete with one game's memory. Shovel Knight, which raised about $300,000 on Kickstarter, mixes Mega Man's look and boss structure, Ninja Gaiden's short swipe, DuckTales' downward plunge, Castlevania's throwing anchor, Super Mario Bros 3's level map and Zelda 2's towns.

Copying a single game means competing with players' memories of it, which are better than the game itself. The result feels like 8-bit games in general. "Instead of trying to copy a specific game from yesteryear, Shovel Knight borrows liberally from the entire NES catalogue."

Design for how old games feel in memory, not how they played. Players remember old games as bigger, better looking and better sounding than they were, and recall the epic moments while forgetting the grinding and one-hit kills. Matching the real thing disappoints.

"Old games look better, sound better, and feel better in our heads."

Keep retro design's strengths: one mechanic, teaching through levels, fast starts. Shovel Knight keeps the single-mechanic focus explored in many ways, chunky characters and grid-like levels for precision, secrets, bosses, level design that teaches instead of tutorials, and play that starts within seconds.

Drop arcade-era punishment but keep the familiar hazards fair. There are no lives, few cheap hits and no respawning enemies. Knockback stays, but air control lets you recover, unlike Castlevania where knockback killed players again and again.

Punitive death systems existed to stop players finishing in an afternoon. "It's not afraid to throw away the stuff that sucked about those games."

Reclaimable loot and breakable checkpoints give death meaning without restarts. Dying costs money you can win back where you fell, borrowed from Dark Souls. Breaking a checkpoint pays a big load of loot but removes it as a respawn point, so players choose their own difficulty.

The loot loss adds tension without replaying whole levels, and the checkpoint risk and reward shows the game has ideas of its own.

Keep the reference to dated tropes but turn them around. Many 8-bit games were about rescuing a girlfriend, sister or princess. Shovel Knight nods to that setup but makes Shield Knight strong and capable.

Judge nostalgic games by four tests: borrow, keep, modernise, rose-tint. Borrow widely, keep the best, modernise the rest and present it with a rose-tinted retro look. Hyper Light Drifter follows these and works; Mighty No. 9 copies only Mega Man, limited lives included, and recalled its worst traits.

Craft backs the nostalgia: it was built by ex-WayForward developers with years of 2D platformer experience.

Quietly break hardware limits so the game matches memory. Shovel Knight uses widescreen, multi-layer parallax like a Super Nintendo, more sprites per line without flicker, more particles, and more colours and palettes than the NES allowed.

Real NES games faked depth with animated tiles and striped backgrounds, as in Shatterhand, Return of the Joker and Sword Master. Mighty Gunvolt, more faithful to the real hardware, looks too plain by comparison, and few players notice the tricks.

Evoke an old sound chip while dropping its audio compromises. The music mimics Konami's Famicom-only VRC6 chip, which added three channels to the Japanese Castlevania III, and sound effects play over the music instead of cutting into it as on the NES.

"This game cheats and plays both simultaneously."

Borrow an under-used move and tune it for usability. The shovel drop comes from Zelda 2's downward thrust, but you don't hold down, so your thumb can steer in mid-air, and the shovel's wide collision forgives near misses.

It was one of Sean Velasco's favourite NES moves, under-used in Zelda 2. DuckTales' pogo-jump and Mario's ground-pound were other inspirations.

A signature move should join combat and platforming, then shape the levels. The shovel drop bounces high, so it is both weapon and platforming tool, and many enemies and objects are built around it: magic books, giant gears, bouncy beetles, sea snakes, jellyfish and an angler fish.

Gold Armor blocks at the front and above, so whichever way you attack "he's blocking you in some way." Since 2014 the game has added three more heroes, each with its own move.

When levels are reused, put the mastery in the controls. Plague Knight reused Shovel Knight's levels, so his bomb burst carries the complexity: charge and release to launch halfway across the screen. Skilled players clear stages in half Shovel Knight's time.

Safeguards make it learnable: an identical trajectory every time, regained control near the end, a neutral jump cancel and bomb throws that slow your fall. Many platforms became skippable, leaving players asking "Where do I land?"

Answer player feedback with the opposite design in the next character. Players found Plague Knight uncontrollable, so Specter Knight was built to make it "really easy to be cool." His dash slash covers the same distance but only works near targets and shows a landing line.

He has long hang time, falls slowly and wall runs automatically, and got new levels with readable enemy cadence, justified by planning to reuse them for King Knight. "Every game is an answer to the previous one."

When state is hidden, lean the rules in the player's favour. King Knight's spin looks the same whether or not his bash is available, so players must feel it out, but getting hit grants a free bash.

The team had "a million discussions" about an indicator; David D'Angelo compares it to Mega Man X's unseen dash count. Planned Mario-style momentum was cut because the bash already sends him so far, and the level reuse never happened.

Where you put complexity, controls or levels, sets the learning curve. Simple controls leave complexity to the levels and flow well but can feel prefabricated; complex controls carry it themselves and suit mastery and speedrunning.

Taking control away, as the burst and bash do, steepens the curve. In a blank room Shovel Knight can barely do anything while Plague Knight reaches almost every corner.

Make an added genre optional so nobody is forced through it. King of Cards includes a card battler, but "you never need to play the card battler."

Blend genres that already share structure. For Pocket Dungeon, Yacht Club noticed roguelikes and action puzzlers share grids, simple controls, randomness, runs from scratch and thinking several moves ahead.

"It was easy, and natural, to put them together."