Voadam
Legend
2e had a d10 based init where lower was better and bigger weapons and higher level spells generally added more to the roll.We ditched level limits, and instead gave humans +1 to any one ability score and the ability to multiclass (with a fairly generous list of allowed combinations). We added dex bonus to initiative (or subtracted - lower was better, right?), and did max hp at first level. Probably some other stuff I am forgetting, it is over 20 years since I last played AD&D.
That was for 2e (with bits and pieces of BECMI brought across from time to time - mostly monsters). I never played 1e.
We also did "dead at -10 hp" ("hovering at death's door"), but I cannot remember if that was a house rule or an official variant we switched on. 2e had a lot of those.
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glass.
1e had d6 init with a lot of complications but high was good.
2e had dead at -10, while 1e had if you hit 0 exactly you were unconscious and not dead and losing 1 hp/round until -10 and dead if untreated. Otherwise dead at -1.