500 MB
This game is built for mobile devices.
You can still save it to your library and install it later.
An idle RPG that keeps unfolding into active platforming, crafting, bosses, and a startlingly large skill tree.
Idle Slayer is a free idle game released under Free to Play. It runs on Android, iOS, needs about 500 MB of disk space, and requires no account, payment or trial. Download it from the official site at https://idleslayer.com/.
Install Idle Slayer from its official Steam page for Windows, or use the official Google Play or App Store version on mobile.
Minimum
Modern web browser
Recommended
Modern web browser
Yes, with optional in-app purchases.
Use Steam for the native Windows build or the official mobile store for your phone; no standalone Windows installer is offered.
Windows via Steam plus Android and iOS.
No maintained, sanctioned mod ecosystem was found.