I shipped a browser game that was 8KB. Okay, plus 30 million lines of Chromium ;)

Most of my games are roughly in that range though. I think my MMO was 32KB, and it had a sound effects generator and speech synth in it. (Jsfxr and SAM)

I built it in a few days for a game jam.

I'm not trying to brag, I'm trying to say this stuff is easy if you actually care. Just look at JS13K. Every game there is 13KB or below, and there's some real masterpieces there. (My game was just squares, but I've seen games with whole custom animation systems in them.)

Once you learn how, it's pretty easy. But you'll never learn if you don't care.

You have to care because there's nothing forcing you. Arguably The Last Ninja would have been a lot more than 40KB if there weren't the hardware limitations of the time.

They weren't trying to make it 40KB, they were just trying to make a game.

In my case, I enjoy the challenge! (Also I like it when things load instantly :)

I think I'll make a PS1 game next. I was inspired by this guy who made a Minecraft clone for Playstation:

https://youtu.be/aXoI3CdlNQc?is=sDNnrGbQGJt_qnV6

P.S. most Flash games were only a few kilobytes, if you remove the music!