Hey Mark, good question... I firmly believe that LASSIE has been engineered to make changes as easy and painless as possible; but the simple truth (that applies to anything in life) is that doing it once – right – is easiest. Considering your questions though: to add a room later would be pretty simple. Room layouts exist as independant descriptions which are linked together with a TIM-e script (changeRoom(#roomID)). You can always add new layouts then insert TIM-es into your existing game to incorporate the new rooms. Graphics and animation are fast updates assuming the pixel dimensions of the updated images do not change. LASSIE utilizes a graphics library, so changing a graphic in the library will update it everywhere it appears in the game. Same with Flash animation. If your replacment graphic has different pixel dimensions though, then you will need to go into your room layouts and adjust coordinates to account for the offset in the image size. Pain in the butt, but it's the price you pay for not pre-planning. As for puzzles: that totally depends on the complexity of the puzzle you are trying to achieve. Maybe some of the game developers on this forum can answer that in better perspective. My practical use of my own application somewhat limited. I've just been building it :D

Simpleee
Mark, try to play a little changing things in the demo game in the lassie web. It`s just takes a few minutes (really), and you will see how simple is to make those changes.

It really is quite easy to edit things, add/delete sprites, rooms, etc. As for puzzles, I had written a work flow of my game, pretty much coming up with puzzles I've wanted, but as I've been working on the rooms I've found better ways of doing puzzles and have even gone back to a room to add more puzzles. So it's all quite simple.

I've been running it on an 800 MHz G4 with 512 MB ram and it pretty much runs fine. Some of the animations slow down a bit when they're really large, but that's because of the constraints of the editor (they'll speed up once compiled.) On a 1.67 GHz G4 with 2 Gigs ram it runs REALLY smooth.