Since it's been asked, here are some hints for "Just a Minute" and "Just a Minute Part Two".
Part One
How easy or hard this is really depends on the version. I first played it on the Mac, where it's easiest: dig into the little box just before the wall, bash, release rate 99.
Here's how I solved the Genesis version, which is probably the hardest: start bashing straight away with the first lemming. The second lemming digs into the little box. The basher should now dig until he's just higher than where the other lemmings are trapped, then carry on bashing. Release rate 99. At a certain point (you'll have to experiment to get the timing right), bash the crowd out of their box. The idea is that they walk down the basher's tunnel and reach him just as he breaks through -- you don't lose time with lemmings walking all the way back to the start. This solution should work on all versions. (To be honest I didn't find this solution; ccexplore told me it.)
Part Two
Well, on the Mac, you just bash with the first lemming, dig with the second low enough to keep the lemmings contained and then bash, release rate 99. This is a bit random and sometimes fails, but you should usually succeed with about a second left.
On the Genesis, start by increasing the release rate to around 50. Again bash with the first lemming, but dig behind him with the third. Have the second lemming turn round and dig just in front of the other digger; then when they are deep enough to hold the lemmings, have them both bash, opposite ways, to make a holding area. The rest is the same as Part One. Again, this should work on all versions, since the Genesis version seems to be the slowest.