Lemmings

Lemmings chuck themselves on to PSP - PSP News - gamesradar.com: "As the trickle of releases for PSP quickly becomes a torrent, we're starting to notice some definite groupings. Alongside the original titles and the shrunken PS2 games, there's the old school classic that's been brought back from beyond the grave for some portable afterlife."

one of my few favourite games from about 1991
but I used to take it much too seriously

The LemNet Chronicles: "Lemmings is a strategy game, available for many different platforms.

The game goes like this: a number of blue & green creatures (lemmings) fall into a level, which consists of ground (rocks, wood, strange things), an entry (which the lemmings fall out of), an exit (which the lemmings must get to)
and sometimes interactive objects (in the game in the original style, these are traps, but in the other games they can be a lot of different things).

You are given a certain amount of skills (climber, floater, bomber, digger, basher, miner, builder, blocker) which you must use to help get as many lemmings as possible to the exit.

While this is easy on the first few levels, the levels can be VERY difficult indeed. "