TGB Dual has been designed as the perfect GameBoy and GameBoy Color emulator on the market. It supports a couple of ROMs simultaneously. In other words, you can emulate two games and link them up – for example, you can trade Pokemon between a couple of different games. Two people can use the same keyboard to play games with no issues at all too. TGB Dual was simply way ahead of its time. While the project has most likely been abandoned, the newest version (which is quite old) can easily run on the latest versions of Windows with no issues at all. It only runs on Microsoft Windows.
Initially released in Japanese, the emulator has been translated into English as well. It has an intuitive interface and it can be downloaded and used for free. TGP Dual also supports various plugins for a few different services to boost the overall experience.