Indiegala are giving away free Steam keys for Terra Lander.
Inspired by the classic Lunar Lander video game, it has retro style vector graphics but has been updated with a few modern touches (such as enemy gun emplacements!). Looks like a fun little time waster.
Overall user reviews are 'Mixed', although I get the impression that it deserves better - there are many genuine positive reviews. No Trading Cards.
It's been available before so existing Indiegala users may already have this key.
You'll need a (free) Indiegala account, and if you haven't already done so you may need to link it to your Steam account and/or join the Indiegala group on Steam.
Ah…. takes me back to primary school… playing moon lander on a BBC Micro (or something similar, might have been Lunar Lander?).