Berserk Falcon, You may not have enough RAM. The game seems to require 2 Gigabytes. You can try to modify the WINDOWS_clickToRun.bat for it to contain
java -Xmx1024M -jar "Super Smash BS.jar"
effectively just replacing the 2048 by 1024. It will tell the game to try to use only 1 Gigabyte of RAM. I cannot ensure you that it will be stable but it ran without problem when I tried it.
snuffysam, first of all, kudos for this game. It went a long way since your first post, you persevered and it delivers! I finally tested it so I can tell you some improvements that could be good in my humble opinion (but the game is still great!).
Compression/Optimization, I am not sure it is in your priorities, but the game is really heavy. The 500MB archive size is what made me not try it before (too long to download) and 2GB RAM seems quite a lot for running a 2D game (and the heap allocation problem is maybe somewhat common)
Linux, I have no launcher for my system while the game runs flawlessly with 'java -Xmx2048M -jar "Super Smash BS.jar"'. That's not a big deal, just feeling a little excluded without reason
Revival platform, I did not see it until my third game. It disappears immediately if a key is pressed when dying. To solve it, you may begin to consider inputs after death only after all the buttons was released. From experience, at death players tend to release all buttons (just not immediately) before taking their next action.
Escape quits the game, I often use it to go back in menus, but it quits the game. Also, being able to (easily) quit the game without confirmation in the middle of a fight does not seem appropriate. We can surely get used to it, but it feels strange the first times.