Side-scrolling platformers, playable in your browser

American PC platformers of the early nineties have a specific texture, and it comes from a technical problem. Consoles had hardware scrolling; PCs did not, and EGA cards actively fought anyone who tried. John Carmack's adaptive tile refresh — written for Commander Keen in 1990 — is the trick that made smooth side-scrolling possible on a PC at all, and almost everything on this page descends from the studios that followed once he had proved it could be done.

Seven of the ten are Apogee titles, which is less a curatorial choice than a licensing one: Apogee and 3D Realms have been unusually willing to let their catalogue stay free.

Where to start

Commander Keen — The one the technique was invented for. Still the best argument on this page that a constraint met head-on produces something better than the constraint's absence would have.
Cosmo's Cosmic Adventure — Apogee at its most charming — Cosmo's suction-cup hands stick to walls, which turns every level into a climbing puzzle rather than a jumping one.
Bio Menace — Free in full, all three episodes, and considerably meaner than its Keen-adjacent art style prepares you for.
Monster Bash — Underrated: a horror-comedy platformer with genuinely good animation, from the period when Apogee had money to spend on artists.
Jetpack — The odd one out, and closer to a puzzle game than a platformer. Adept Software released it free, including its level editor.

Free in full, versus free first episode

The split matters more here than in any other category. Bio Menace, Alien Carnage, Xargon and Jetpack were released as complete freeware by their rights holders — all episodes, nothing withheld. Commander Keen, Cosmo's Cosmic Adventure, Crystal Caves, Monster Bash and Hocus Pocus are the free first episode of a larger shareware game.

Both kinds are labelled on their own pages, and the fully-free ones carry a FREE badge in every listing on the site.

Two games that look broken and are not

Worth saying plainly, because it cost us time to work out and it reads as a hang. Xargon opens on a prompt asking whether you want digital sound and then waits — press Y. Hocus Pocus opens on a sound-credits screen that also waits for a key. Neither is loading, neither has crashed; both are doing exactly what they did in 1993, on a screen nobody remembers because you only ever saw it once.

Every platformer here also has an on-screen keypad on touch devices, including an ENTER key for menus — added after we found that tapping a button quickly could send the press and release inside a single emulated frame, so the game never saw the key go down at all.

Other categories: Classic shooters · Side-scrolling platformers · The Windows desktop classics · Card games · every game and guide

Frequently asked questions

Do these need a keyboard?

On a computer, yes — they are keyboard games and the arrow keys plus one or two action keys cover everything. On a phone or tablet each page shows an on-screen pad matched to that specific game's controls.

Why is Commander Keen only one episode?

Because only the first episode was ever free. Marooned on Mars was the shareware release; the other two episodes were sold, and still are. The page says which one you are getting.

Are these emulated or rewritten?

Emulated. These are the original DOS executables running under DOSBox in WebAssembly, so the game logic and the artwork are exactly what shipped.