It's worth a try to pay $1 and see if this is one of the DRM free games. If not, big deal, it was only $1 for four games.

Most older games that didn't require any sort of DRM when originally released that are later added onto Steam don't have any DRM required. So you can go to your Steam library, right click on the game, go to properties, local files, browse local files, and more than likely play it from there without being required to open Steam again.

Unless you're going to buy a copy and share it with all your friends, what's the point in not getting it on Steam if it's cheapest there? Because Steam might not be running in 20-30 years? If it's not running in 30 years, then who cares really. You lost $1. You know what I'm going to do in 20-30 years if I can't play digital games I paid for. I'm going to download them illegally. I mean, what PC game can you not download? Many of them are older than 30 years and can still be found. Will anything be different 30 years from now? Probably not. Infact, the games that are new now will be just as easy to find as the 30 year old games are now.