Aegis Defenders is a pixel-art 2D action-platformer tower defense game released in 2018. It's also, as we said in our review, quite good, particularly if you can find someone to play co-op with. That may be a little easier in the very near future, as the Humble Store is giving it away for the next three days.
Until 10 am PT/1 pm ET on May 17, or while supplies last, a copy of Aegis Defenders on Steam is yours to claim and keep, for nothing more than the effort required to go here and click the button that says "get the game." Do that, and you will be granted a Steam key, which must be activated prior to 10 am PT on May 21, so you should probably do that right away to ensure you don't forget about it.
(Luckily it's redeemable directly from the Humble page, so it's like two extra clicks to complete the process. No need to wait on it.)
The giveaway is there to draw your attention to the Humble Store Charity Sale, which has discounts of up to 50 percent on all games published by Humble, including Void Bastards, Them's Fightin' Herds, Crying Suns, and Slay the Spire. Most of the games on sale can also be packaged together in a Build Your Own Bundle deal, and funds raised will go to support Partners in Health, Doctors Without Borders, Direct Relief, and the International Rescue Committee. The sale is on until 10 am PT/1 pm ET on May 18.