There really is nothing better than free stuff, especially when you find yourself without a console, without a spare $50, and armed only with a mac, a system which isn't known for good gaming. So what do you do? You delve into the Steam archives and try out a bunch of mac supported free-to-play games. Here's a few that are actually quite good.
1. Emily Is Away
Probably the most original, and emotional free game I've played. Emily Is Away simulates an early-2000s IM chat with a girl called 'Emily.' Over the 'years,' your relationship with 'Emily' changes based on a series of choices you make in the conversations you have with her. If you even used AIM or MSN in 2006, this game will totally hit you right in the feels.
Robocraft is a game where you build your own robot, and destroy the shit out of other robots, in single-player and intense multiplayer battles. The more robots you blow up, the more gear you earn to upgrade your bot. Explosions, robots, customization, what more could you want?
3. Dota 2
As the most popular game on Steam, Dota 2 is worth a mention. The game is a huge multiplayer online battle arena (MOBA) game developed by Valve (Portal, Half-Life) which matches two teams of 5 players head-to-head, with the aim of destroying the other teams 'Ancient' building. There was also a documentary made about Dota 2's predecessor, DotA called Free To Play, so it's a pretty big deal. If you're into League of Legends, team, and strategy games, then this is as good a place as any to start.
4. Marvel Heroes 2016
I was unsure about how this one would go down, as a free-to-play game based on Marvel, my hopes weren't high. However, I was pleasantly surprised. Marvel Heroes 2016 allows you to pretty much instantly become one of your favorite heroes; and not just the ones from the MCU. You can take on Captain Marvel, Doctor Doom, Nightcrawler, Deadpool, and so on - which for any Marvel fan, is pretty cool. You can work on your own, as a team or in the multiplayer stage taking down Marvel's most iconic villains.
Remember Snake? That 8-bit Nokia game from 2002? Well Worm.is is kinda the updated version of Snake, and is painfully simple to play and painfully easy to get hooked on. The aim is to eat all the food, grow big, and try not the get eaten by other players. However, if you just go to slither.io or agar.io you can find basically the same game without signing up for anything.