In 1998 my family got its first PC, and my uncle helped me install some games.
One of my favourites was one where you played as a frog.
You were in a castle(?) and the gameplay consisted of jumping around tiles to pick up items (keys??) and make it to the exit on the other side of the map.
The hitch was that there were enemies on the map as well. Whenever you moved a tile, they moved a tile (towards you!) so you had to like, plan out your route so that you could get all the items and make it to the exit without any of the monsters getting to you.
I've been trying to google this for ages but I just can't seem to find out what game it was. If anyone has a picture of the first level or the starting-screen, I'd recognize it immediately, I know that for sure. (I was very bad and very rarely made it past the first level XD)