GOG's weekend sale is all about the "Square Enix Squad," but it's actually slightly misleading since the promotion includes a number of titles published by the likes of Eidos and Hasbro. Case in point: you can get Deus Ex Gold, Thief Gold and their sequels for £2.46 each, alongside Tomb Raider and Hitman: Codename 47. Squeenix now owns the rights to these IPs, and this is potentially a cheap way of getting involved in the series lore before the likes of Hitman: Absolution hits the shelves.
Legacy Of Kain: Soul Reaver and its sequel are also on sale for a paltry £1.48.
You can check out the full promotion here, but remember that some of these games are discounted in franchise bundles every so often.