its not really a single achievement as such...
but over the past few days i've just improved on other cubes by a ridiculous amount - for example, i was averaging around 6:00-9:00 on the megaminx - i had no lookahead, and no last layer system for corners OLL or PLL.
i tried again soon after jude got a megaminx, because he demolished my times instantly (not to say he also learnt about 14 LL algs in a night). so i did a couple more solves, and now average around 3:45, a reduction by nearly 50%!
and similarly, with the 4x4, i went from a 1:50-2:00 average, suddenly down to sub 1:40 at least, and over the weekend i got 4-5 sub 1:25 solves, with a 1:19.xx best, and a 1:2x(1-3?).xx with double parity. and i seriously think that if i improve my centres (still around 18-30s) and my 3x3 part (30-45s) then i can easily average that.
not only that, i also got an average of 12 of 15.xx, and over the past few evenings I've had many, many 12.xx and 13.xx non lucky singles, with most session averages being around 16s, and less than a month ago was i pushing sub 18s!
i just dont know whats happened!