Often game jams produce a lot of interesting ideas rendered in basic, barely-legible programmer art, but themes like the cyberpunk jam or the space cowboy jam seem to attract artists as much as game designers.
Case in point: The Last Night, made by brothers Tim and Adrien Soret. It’s a “Blade Runner + delicious pixels”. It’s inspired by Flashback and games of its era. It is by implication a stealth game, though it contains no mechanics to support that so you have to shoot everything. It is three minutes long, beautifully drawn, and full of great music. Play it in your browser at that or this link.