Buyers beware, this is a different version from the one in steam/xbox. To start, there's no multi-language support. You can't change to a different language. To make matter worse, the font size is not adjustable. It's small and intelligible even in 1080p monitor, or esp. in high resolution. The letterings in a word actively clusters together. "Wound" show up as "vond" or even "vnd"/"vod". The interface change is tolerable, but lack of multi-language support and words becoming too hard to read in a text puzzle are simply too bad for this game. Other than this, the game itself is a gem. Got no complaint in that aspects. Sadly, it's just an inferior version. Hope GOG or the developer/publisher fixes it in the future. Have to ask for a refund now. In this state is nigh unplayable.
Even with the recent revival in turn based combat genre, this game is still unique in its complexity and strategy. For instance, with Xcom or Xcom-like, the positions of enemy and the start of battle are randomized and steamlined, along with other features. This is not the case with JA2, there are patrol routes and fixed position guards, etc. In general, you have more control over how you approach a battle, night time stealth raid or day time full on assault. Also, even for newer players, get the 1.13 unofficial version. It's not the vanilla experience, but it offers tons of customization options and make the game smoother to run in newer machine.