Click the furnace or hold Space to earn Hellwatts and Heat. Buy machines on the left, press O for Overdrive when Heat is full, choose a Sin Pact, and keep building until you discover the Doomsday Core. That discovery ends the browser demo, typically after 10–15 minutes according to the developer. The nine Circles belong to the full game.
Play for free
Open the official game page, click Run game and select New Game. WGNSpear released the title on October 23, 2026 at 14:18 UTC and announced the desktop-browser demo on October 24 at 12:41 UTC. The web build is a demo, not the complete Windows download.
Step-by-step progression
- Stoke the starting Pathetic Furnace with a click or by holding Space. Each stoke produces Hellwatts, which pay for machines, and Heat, which fuels Overdrive.
- Inspect the machine list on the left. Buy affordable machines to expand production beyond manual stoking. Check the displayed prices rather than assuming an unverified perfect purchase order.
- Watch the Heat meter. When it fills, press O for Overdrive, a temporary production multiplier. Remember to use the burst while growing the plant.
- Open Pacts with P. Read the benefit and trade-off of the available Sin Pact before signing. Active clicking and idle production call for different choices.
- Press E to handle plant incidents for rewards. The developer explicitly says you can also ignore incidents without a penalty.
- Keep buying machines and using Overdrive until you discover the Doomsday Core. The developer calls discovery the demo endpoint, not necessarily purchasing or completing the Core.
Controls
| Input | Effect |
|---|---|
| Click furnace / hold Space | Produce Hellwatts and Heat |
| O | Trigger Overdrive |
| U / P / C | Upgrades / Pacts / Circles tabs |
| 1 / 2 / 3 / 4 | Buy 1 / 10 / 25 / maximum |
| E | Handle an incident |
| D | DEVOUR with Gluttony |
| Esc | Menu |
Pacts, pitfalls and builds
The full game has seven Sin Pacts and allows two equipped at once. Sloth rewards inactivity, Wrath rewards timing, Greed rewards saving, and Gluttony offers DEVOUR, which consumes reserves. Every pact has a trade-off. The demo only includes early progression; do not expect all seven pacts or their corrupted versions. Choose according to the description shown in your run, not a supposedly proven strongest pair.
If O seems unresponsive, check the Heat meter first. Number keys change buying quantity, not movement. The browser demo saves locally, but its save does not transfer to the downloaded game.
FAQ: demo versus full game
How many machines are in the demo? The developer specifies six types. What does the full version add? The Doomsday Core and Eternity Engine, seven pacts and corruption, nine Circles of Hell, and 57 achievements. Does offline income work? The full game allows up to two hours after purchasing Unpaid Overtime; the demo should not be assumed identical. Do pacts affect offline income? A player asked on October 25, but no verified developer answer was available. Is the full version free? The creator advertised a free-to-keep offer through November 4, 2026; confirm exact conditions on the claim page.
Summary and sources
Stoke → buy machines → fill Heat → Overdrive → choose a Pact → discover the Core. The plant may be condemned to eternal work, but its browser trial ends on time. This guide uses the developer's documentation; it does not claim a personal completion, measured output rates, or an optimal build.
Sources: game and controls; browser demo announcement; 1.0 launch announcement. Checked October 25, 2026.
