Oh yes, I remember TWAT, I played it and the final boss killed me as I ran out of ammo (it must have been very close to death itself). :D
I also experienced older engines to be a lot more prone to parts of your project just disintegrating (map data, mostly), kind of, or simple things taking forever to do. Though using something like the Build engine (if there's even a "generic" version of that around, I haven't looked) for a jam game might be a fun change some time!