add info about level generation

README.md

@@ -140,4 +140,4 @@ When you are satisfied with your filter selection, click the "Find Seeds"-button
 
 ## Known limitations
 * Can't filter the first item in the dice shop, because it isn't immediately available on the first frame of the level. It pops out of the prize dispenser (you can see it bounce if it's in view when the level loads).
-
+* The deeper a level you choose, the longer it takes for each seed to process. That's because every preceeding level needs to be generated, you can't just skip to e.g. 4-2, because the level generation will be different compared to if you followed the path from 1-1, 1-2, ... to 4-2. You can experiment with this yourself by using Overlunky: load a specific seed, and play the first two levels, look at what 1-3 looks like. Then restart the seed, and create a warp door to 1-3, and you'll notice it looks completely different. So, unfortunately it seems that individual levels depend on the preceeding levels. When you request a filter that applies to level 7-4, all the preceding levels have to be generated, taking up a lot of time.