$ java -jar Downloads/minecraft.jar
Created new window in existing browser session.
27 achievements
174 recipes
Setting user: kaasinees, 6492966854971641986
Exception in thread "Minecraft main thread" java.lang.UnsatisfiedLinkError: /home/desktop/.minecraft/bin/natives/liblwjgl.so: /home/desktop/.minecraft/bin/natives/liblwjgl.so: wrong ELF class: ELFCLASS32 (Possible cause: architecture word width mismatch)
at java.lang.ClassLoader$NativeLibrary.load(Native Method)
at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1928)
at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1825)
at java.lang.Runtime.load0(Runtime.java:792)
at java.lang.System.load(System.java:1059)
at org.lwjgl.Sys$1.run(Sys.java:69)
at java.security.AccessController.doPrivileged(Native Method)
at org.lwjgl.Sys.doLoadLibrary(Sys.java:65)
at org.lwjgl.Sys.loadLibrary(Sys.java:81)
at org.lwjgl.Sys.<clinit>(Sys.java:98)
at org.lwjgl.opengl.Display.<clinit>(Display.java:132)
at net.minecraft.client.Minecraft.a(SourceFile:187)
at net.minecraft.client.Minecraft.run(SourceFile:644)
at java.lang.Thread.run(Thread.java:722)

https://bugs.gentoo.org/show_bug.cgi?id=391243

solution: add 64 bit natives and fix natives paths, townsgame does it properly.