My main achievement was in Football Manager 2010 when this month's work ended in establishing Rotherham United as the leading football club on the planet in a mere eight years...
Rotherham United:
2009-10, League 2 winners
2010-11, League 1 winners, JPT Trophy winners
2011-12, Championship winners
2012-13, 8th in PL, Carling Cup winners
2013-14, 2nd in PL, EL quarters (I believe...), CC winners
2014-15, 2nd in PL, CL winners (1-0 Man City, Buonanotte)
2015-16, PL champions, CL finalists (0-1 Milan, Pato), FA Cup winners, Club World Cup winners
2016-17, PL champions, CL winners (1-0 Chelsea, (the Manc) Anderson), FA Cup winners, CS shield winners
So 2 Champions League titles and 2 Premier League titles in eight years without adjusting the starting budget is quite handy I guess...

What are your craziest ladder climbings and results in domestic and continental glory?