I've actually had a lot of trouble with applets using Slick, lots of bugs, freezing and not working on mac/linux. Any experience with this?
Maybe use Java Web Start instead of applets. I use Linux and I have rarely problems with applets, what you report is strange.
An example would be this:
http://staff.washington.edu/shinyy/martygame.htmlSometimes it works fine, other times it freezes and even more weird sometimes the fps goes way out of wack.
Anyway, I was probably going to look into learning how to do that or possibly switching to flash(though I probably shouldn't talk about that here should I?

)
Nice little game - Ran fine, but couldn't get past level two.. The gate would not open

try stepping on the button
if thats not working then dear lord we have a game breaking bug here