About badtimesimulator.org

badtimesimulator.org is a small, independent site built around one game: Bad Time Simulator, jcw87’s fan recreation of the Sans fight from Undertale. The domain has hosted the game since 2023, and this version of the site was rebuilt in September 2026 as a plain static site so that it loads fast and keeps working without a database or a server process behind it.

Everything on the site stays in one lane. Alongside Bad Time Simulator you will find a hand-picked set of boss fights, bullet-hell and survivor games, the hardest platformers and a few horror classics, each with its own write-up: what the game is, how it controls and a few tips that would have saved us a hundred deaths. We are not trying to be a catalogue of a thousand titles; if you came here to beat Sans, the next thing you see should be worth your time too.

How the games work

Bad Time Simulator itself is jcw87’s open Construct 2 build, hosted on this domain and running in your browser. Nothing is fetched from anywhere else once the page has loaded. The other games are HTML5 builds embedded from the game host that serves our sites. Nothing is installed, no account is needed, and a game only starts downloading when you press Play.

Who writes the content

The descriptions, control guides, tips and answers on this site are written by the people who run it, after playing the games. Where we describe a mechanic, it is because we have used it. If something we have written is wrong, tell us through the contact page and we will fix it.

Ownership and rights

Undertale, Sans and the music in the fight were created by Toby Fox and are his property. Bad Time Simulator is a fan project by jcw87. This site is a fan site and is not affiliated with, endorsed by or sponsored by Toby Fox or jcw87. All other games remain the property of their respective developers and publishers. If you own a game listed here and want it removed, get in touch and we will take it down.