This little game is an absolute blast.
I didn't have high expectations but Maniac is some genuine run & gun mayhem. The reviews and the description on the store page make this game out to be a roguelike old school GTA, which is fairly accurate.
However, while in GTA you get a variety of missions and side quests that advance an overarching story, Maniac has just 1 mission. Stay alive for 20 minutes and kill & destroy as much as you can before a nuclear strike hits the area.
Don't be fooled by the (dare I say) "cute," even "cozy" graphics, Maniac is incredibly violent and bloody, people scream in terror and pain, lots of death and things blowing up, you get to steal and destroy all sorts of vehicles.. it's really quite sensational. I have to admit I was blown away by how mindlessly fun this game is.
I'm hopeful that the developers plan on releasing more content for the game, the potential for DLC, expansions, sequels, etc., is virtually limitless.
Also it plays great on Steam Deck.
I highly recommend this game.