HARP's combat is inherently faster than RMs because you only have a single roll, there is no separate critical roll. Even if you use the Hack & Slash rules from the Harper's Bazaar (which I like), there is still just one roll. And, yes, without the 30+ different tables to flip through, combat can be even that much faster.
In HARP you have tables by critical type - crush, puncture, slash, etc. - with mods depending upon the weapon used, namely the size of the weapon. The size modifier is only applied if an attack resulted in a hit, meaning they succeeded in connecting, thusly modifying the result up (for more damage, used for larger weapons/attacks) or down (doing less damage, used for smaller weapons/attacks). So, if two combatants attack something, and they both get the same result, and everything else is equal/normal (no special abilities or magical effects) the character with the 2-handed sword will do more damage than the one with the dagger. (Hack & Slash just has different columns for the different size categories of weapons: tiny, small, medium, large, and huge.)