OK then. In this case, it's not really a problem since it is straight out competitor for Steam and their service and idea is different... It's something like going to McDonald's and take the receipt to Burger King just to ask for the product there, it's just not going to work. If the store sold keys to multiple stores, I would see more hope but with GOG it's not going to work. Anyway, I do have few suggestions though.
- If the game(s) came with any sort of activation or serial then try them on Steam (doubt this, but worth a try).
- Add them as a
Non-Steam Games so you can launch them through Steam (doesn't add them into your Steam library for re-download but you can still play them through it until you uninstall).
- Start using
GOG Galaxy (haven't used it myself yet but should be similar to Steam).
- We moderators are not responsible for the Steam keys, but you can contact
Jens and/or
Thomas directly (I think Thomas will say to contact Jens, but I still mentioned him anyway). However, please note that they are currently working on new secret stuff and rarely visit here so it might even take weeks or months to get your first answer and even then it might be a 'no'.
- As the last thing I will say that if you really, really want the Steam version and none of the above don't seem correct for you or didn't work out then wait for a sale on Steam (they probably have some Easter sale and if not then there is definitely a summer sale in few months). Penumbra Collection is usually 75-90% off and you don't have to pay for more than 3€.