whole temple
The ability to save the current state of execution and then reload it.
This would help immensely when debugging, so that you can rerererun code without having to fiddle with breakpoints. Especially when you don't want the first time the breakpoint would've tripped.
tepid ivy
never mind just code - if enough state was stored it could potentially allow replaying for ASICs as well (though some care would need to be taken to ensure the design/code haven't changed between state save and state load.. compensating for that in a manner similar to for example Visual Studio's "edit and continue" functionality would be a significantly larger challenge)
shy shadow
This feature previously existed, I am pretty sure altrag was already on the server at that point
Stuffe asked whether or not the feature should be reimplemented after an engine upgrade, and multiple players said they never actually used it
tepid ivy
There was the step backwards function (that has since been removed) but that's only kind of the same thing.. sort of saving a stack of states one tick at a time behind the scenes whereas I read this request as an explicit user-controlled state save (which would be more useful in the long run is up for debate and probably depends on each user's workflow and possibly even how they work on each individual level..)
personally i didnt use the step back function all that much because it was way too granular.. having to step back dozens of ticks one at a time to get where you wanted is just as burdensome as having to step forward. Plus the step back function never quite worked "right".. mostly right but there was always some quirks (at least I recall running into some issues.. of course back then there was a lot of issues everywhere.. it was still very early dev and things have improved significantly since then 😄 )