Yes, TIS-100 is super fun to optimize!

Shameless plug: I think I made the Signal Averager about as fast as it can possibly be https://www.youtube.com/watch?v=XBfEcxvJ6aY

Factorio is another one for optimization. The main difference is that Factorio is a single puzzle that you optimize continuously throughout the game.

Not a single game I know drives home the concept of "technical debt" as much as Factorio does. Every time I want to automate manufacturing of a new thing, I end up wondering whether I should do a quick&dirty hack on existing pipelines, refactor half of my base, or just build a new one elsewhere...

(And you can't just always keep choosing "build a new one elsewhere", because this increases a literal attack surface and invites literal bugs.)

Never though about it that way, it really seems that Factorio is a very good representation of actual software development without actually containing coding (except for the logic you can do through the cables if I remember).

I've found all the games to have high replay value for the same reason. It doesn't really matter how hard the game is because there are plenty of challenges beyond just passing the level.