Which games do you recommend getting this sale?

Looks like a pretty nice game, I will be trying to trade for it if that doesn't work I will definetly still end up buying it!

Just picked up Subnautica hoping to get into it!

ABZU is a great, relaxing and relatively short experience, about 3 hours long.
Bastion is first game from Supergiant Games, story-driven masterpiece like every single one of their future games.
Batman: Arkham Origins is a third game from Arkham series, not made by a same studio like previous 2 and therefore a little weaker but still great experience. But I would definitely suggest to buy and play Asylum and City first.
BioShock is a must play series, and first game has one of the best environmental storytelling in videogames ever. Beautiful art deco artstyle, which makes it look beautiful even today.
Guacamelee and its sequel are great metroidvania games with lots of humor and some challenging gameplay.
HITMAN 2 is actually a puzzle game, which will maybe come as surprise. :D It has some of the best level designs, and sandbox gameplay can keep you for dozens of hours trying to do kills a different way. You can play levels from previous game in it which is a big plus. I have spent over 350 hours in it.
Ori and the Blind Forest is a classic, beautiful metroidvania with weak combat system (which sequel fully redesigned) but awesome exploration, music, and chase sequences.
Shadow Tactics: Blades of the Shogun is a modern take on a Commandos formula, stealth/isometric/strategy type of game, only it happens in feudal Japan. I never played that type of games, but somehow managed to play it for 90 hours, doing almost all optional objectives and hard mode.
Snake Pass was the biggest surprise in 2018 for me when I played it. Basically a 3D platformer game with no jump. Control scheme which had to be perfect for this type of game to actually work - it is just that. It requires some time to get used to it, no doubt, but when you master it you will love the game.