Vicarate 3.5 (released Jan. 7th, 2021) by Henner Kessler is a fighting game for the Commodore VIC-20.  No memory expansion is required, or can even be installed when playing.  There is support for 2 players when using the Protovision 4 player interface.  In the archive is both a .D64 image and a .PRG file that can be put on an SD card if using the SD2IEC with your VIC-20.  Be sure to load the game with Load "VICARATE35",8,1 as it's a machine language program.

** this version doesn't work with the FB20 launcher, but included in the archive is an Exomizer crunched version that does.

For further information and discussion, visit this post at the Vic20 Denial forums.