Coolthulhu

Get rid of hydrogen and water in places where dupes walk. Use mesh tiles to prevent puddles on dupe walk paths. Oxygen, even hot enough to damage dupes, doesn't transfer heat fast enough for dupes to get stroke.

Does it actually do anything? I keep it disabled just to mark the area as great hall.

You could try ensuring that the magma is never above ~500kg/tile when it cools. For example by allowing it to spread horizontally on an insulated tile flat and only cooling it at the edges where it has already "flattened" into 100kg/tile. When a small amount of magma cools, it cools into an item, not a tile. You can then pick the item with a sweeper, or just leave it to slowly exchange heat with the diamond/thermium tile below it.

If the numbers stay within an order of magnitude of the current ones, the CO2, pO2, chlorine and volcanoes will still be useless for anyone except noobs who don't do math. On average, 1 water geyser is better than 4-5 pO2 geysers when it comes to oxygen production. That's the ratios we're looking at. Someone looked at those numbers and said "OK, this totally isn't stupid".

Oil chain is the only one of its kind. Useful tricks: CO2 pit will prevent rot of all things in it. Unpowered refrigerators are more space-efficient than boxes. Waterlocks (liquidlocks in general) prevent gas mixing. Atmo suits prevent wetness. Liquids are usually much more conductive to heat compared to gases (stat block doesn't show it). Keep a small puddle of water (oil if heat is used) on a building to ensure it quickly exchanges heat with nearby thermoplates. <2kg liquid on a gas vent will make it work even if surrounding gas is >2kg. Make sure the liquid has a place to be squeezed into or it will be deleted (and delete gas that was supposed to be placed there). Diamond window tiles have the highest thermal conductivity of all tiles. Embed radiant pipes in them to maximize heat exchanges with pipes, then use thermoplates to radiate it out into gas.

It's supposed to be 1kw for small, but I've seen them overload conductive wires when powering a circuit with an uncharged battery on it.

That's it. You can't really do anything to improve it in your game, it's all up to Klei.

Klei forgot to balance pacus: until they start starving, they get full taming effects for eating even just 1 kg of algae per cycle. This allows breeding more of them despite almost 0 input. Fish-O-Matic uses that. Refilling feeder with lowest mass possible doesn't really happen by accident, so it can be considered an exploit without invoking "oh come on". There is also the part where pacus never starve to death (unless actually fed, ironically) and thus always lay at least one egg, but the only way around this is to never tame pacus. So it's hard to consider that an exploit.

Possible causes: Your computer is under load, which causes creature AI to get really slow. Observe your ranches - if critters take a long time to start going towards the stable, this is it. It is a big flaw within ONI design that has been known for a while, but hasn't been addressed yet. The paths to grooming station are too long. Most common with dreckos. For hatches and slicksters, you can just make tall and narrow stables (or open stables). Your critters are underfed and prefer to feed instead of getting groomed. Only happens to slicksters and pufts. Gets much worse with the AI slowdown problem. But really, it's almost certainly the AI slowdown. Joys of Unity engine.

Then don't list it among exploits or list the actual exploit behind it instead of listing the game mechanic that is not an exploit. In this case it's bottling up liquids and dropping the bottles that is the exploit - it allows storing infinite liquids in one tile, so it's obviously not intended. Even without it, the list will most likely grow huge and contain stupid entries from scrubs who consider things like sieve heat deletion to be an exploit.

Shocked expression spam happens because dupe AI is too slow when the game runs under heavy load. It also greatly slows down the digging itself, even if the dupe doesn't get shocked.

Some vital parts of ONI are not C# and so not using Unity directly (from what I know it's in C++). For example, map tile heat/germ/volume exchanges. Those would be unacceptably expensive if every tile was a Unity component. Map tile heat/germ/volume exchanges are essentially (or actually) cellular automata and those are strongly parallelizable.

I was pretty sure it was only the miner. In this case, you can build them in a tiny puddle of petroleum that contacts them at one point and exchanges heat with a tile below it. The tile can then be cooled with pipes or contact with a wall.

Keep them in vacuum. Unless something changed, they don't actually exchange heat with their contents.

You could also try spreading the magma so that it never forms blocks. If you drip the magma over tiles with no neighbors instead of collecting it in a tank, it won't reach the necessary mass to solidify into a tile. You can then collect it with sweepers or dupes. This has an added bonus of doubling the generated mass.