Moleculoids Review: An Asteroids Game That Turned Into a Dungeon

The MoleculArcade menu lists six games, and five of them say "Coming Soon": Pac-Protein, Molecular Invaders, Centipeptide, Ribo-Runner and Crispr Command. Four of those names borrow from Pac-Man, Space Invaders, Centipede and Missile Command. The sixth, Moleculoids, is live. Its card invites the player to "Blast through 3D protein crystal structures in this molecular take on the classic Asteroids," adds that the proteins "split by molecular weight," large into medium and medium into small, and closes with "Watch for binding partners that merge into super-complexes!"

Clicking it loads a top-down dungeon crawler. The header comment of the game's main script calls it a "Dungeon Crawler," and the on-screen help reads "Hold click to move," "Auto-melee nearby" and "Right-click to shoot," with a second line for phones: hold to move toward a finger, tap with two fingers to shoot. The player is a small procedurally drawn creature with legs, arms and a weapon, exploring a dungeon generated on a five-by-five grid of rooms joined by corridors. Monsters come in waves. The fifth wave of each level announces itself as "BOSS WAVE!", there are ten levels, and clearing the tenth ends the game in victory.

The game is free, comes from Molecular Reality Corporation, a small company that builds instruments for reading molecules through nanopores, and draws in 3D with the three.js library. I played it for an evening on a laptop and for a train ride on a phone.

The monsters are real proteins

Each monster is a sprite rendered from a real structure in the Protein Data Bank, drawn in ball-and-stick or spacefill and spun through 32 frames. The game sorts them into eight families with their own speeds and hit points: Enzyme, Receptor, Transporter, Structural, Chaperone, Toxin, Nuclease and Antibody. Receptors fight from range, and Structural monsters shrug off knockback. In the monster code, a comment on the tier settings reads "matches original game."

Sprites come from a hard-coded list of 26 entries, of which 17 have image files on the server. Among the small monsters are two T4 lysozyme mutants (102L and 109L), three sperm whale myoglobins with isocyanide ligands (104M to 106M), a DNA i-motif (105D) and a DNA duplex with the antitumor antibiotic duocarmycin A bonded to it (107D). The medium tier includes E. coli RNA polymerase caught in a paused state (10MB), the kinase domain of Fyn bound to the drug saracatinib (10DJ), the GTPase H-Ras (10DC) and three structures of the NMDA receptor, a glutamate receptor of the brain (10EX, 10FD and 10FE).

The list has five large entries and one image. Every large monster in the game is entry 11YE, "Curved structure of mPiezo1 in plasma membrane vesicles," a cryo-EM structure of the mouse Piezo1 channel that the PDB released on April 29, 2026 (Vaisey and MacKinnon, Science Advances). Piezo1 is an ion channel that opens when the membrane around it is stretched. In this game it is every Structural monster, every Antibody, and the boss of the first two levels.

Items

Pickups are molecules with game effects. Glucose restores 25 HP and Heme 50. Caffeine adds 80 percent speed, ATP adds 50 percent to speed and damage, and Cholesterol adds two points of armor under the label "membrane rigidifier." Dopamine is worth 100 points, with the gloss "reward!" Morphine grants invincibility, glossed "pain relief." CRISPR does what its description says, "Instant kill 3 nearest enemies," and Nucleases are the only monsters with a bias toward dropping it, which is fair, since the Cas9 in CRISPR is a nuclease. The rarest pickup, the "Legendary Enzyme," adds "+8 base melee damage," which the item text calls "permanent!" Every boss drops one.

The Asteroids game is still in there

The server still builds Asteroids levels. Asked for level 1, it picks proteins in three weight tiers, four large, two medium and four small, and the large count rises by one per level up to eight. On even levels from 2, and on every third level, it adds a pair of real binding partners, with an approximate dissociation constant and a note on their biological context. The dungeon never asks for any of it; its sprites load straight from the hard-coded list, and the binding partners that "merge into super-complexes" do not appear.

A companion page, Gallerioid, titled "Moleculoids Sprite Review," lays out 60 protein sprites, each with buttons marked Good and Bad. The verdicts can be filtered and downloaded as a CSV file, and the review log opens with "No reviews yet."