Proprietary games will not run on the Raspberry Pi computer. Proprietary games are games that are not open source. Most games are not open source either. This excludes console emulators, the Raspberry Pi computer can run retro console emulators. Even though Portal 2 has a Linux version, the Linux version of Portal 2 is designed for i386 computers, not ARMHF computers. You can't use i386 programs on a ARMHF computer. Even if you had access to the Portal 2 software package that you would use to install on a Linux PC. The package manager would tell you that your computer is not supported.
I'm not a huge puzzle games kind of person. I would search around for puzzle games for Linux, I don't know where to start. You can decide for yourself which puzzle games to install on the Raspberry Pi computer. Here is a link to Debian puzzle games that you can install on the Raspberry Pi computer:
Debian Games Puzzle packages