if you don't know what to use for music and sound-fx or just want to try something new, take a look at VCVRack the free modular synth for any OS. It is great and since it's open source, anyone can contribute with new modules and people are doing just that, including me: for LD41 I made a module out of the game "pong", which can be played or used to trigger and control stuff in a modular patch. Check this video by dag2009, it's a patch built around that module, where the two players are controlled by other modules in Rack.

https://www.youtube.com/watch?v=sWDFf-pyZE4

if you are interested in modular synthesis, there are tons of videos on youtube about using VCVRack or modular synths in general.

end of plug, glhf!