I started to play Commander Keen again after I saw that you can buy it in a Dos Box on Steam. Some 21 years ago I played Commander Keen 4 and now I wanted to try that again. I finished all the levels but I cannot seem to pass the big fish:
I always get eaten by it when I try to swim around:
Therefore I guess that you cannot really get around the fish but just have to hope that it does not come to you.
The big fish is rather fast now. My memories of this level are not that precise, but I think the fish was not that agile when I was five years old.
Could this be an issue with the clock speed of the Dos Box that gives the big fish an unfair advantage over the player? Or there there some other trick to beating this level that I have not figured out yet?