DSL includes this wonderful guide on how to use it effectively. Then again most things do these days anyways.
Running multiple applications, which it has no problem doing.
Wow, a slide puzzle!
Shutting down Damn Small Linux.
Conclusion: Damn Small Linux is entirely functional, and it works on old hardware or computers that are strapped for hardware. Not much else needs to be said, if you want applications and have a middle or high-tier system I would go for Linux Mint.