FOR THE PLAYERS
To run the game, first make sure you have Java installed. After unzipping the file, open your favorite command line tool and navigate to the spaceus-main/spaceus-main/sprite final backup. Run the following command: javac entity/*.java main/*.java tile/*.java
Then run java main/launcher
And a window should open up with the game.
FOR THE DEVS
.java files are not executable, they're just lines of text that need to be parsed by a compiler and turned into executable files. Next time it would be a good idea to look up how to build executable files for Java projects :)
On another note, I find it impressive that you managed to do your first game jam with no game engine whatsoever. There are quite a few problems, for example the collisions don't match with the actual map, and the window is larger than my screen, but that is to be expected for a first jam. Keep it up!