You'll have to download the Epic Launcher to get it and it's only available until the end of the month. But the remastered version of Shadow Complex is officially free to download right now, and any computer with hardware from the last four or five years should be able to run it just fine.
It was just announced at The Game Awards and the official link popped up a very short time ago. But if the prospect of Shadow Complex Remastered got you a little excited, then the sight of the "Free on PC For The Holidays" stamp on Epic's website right now should cheer you up quite a bit.
To install, you'll need to download the Epic Games Launcher and register an account on the Epic website (or directly through the launcher).
Once you've got the launcher loaded up, you'll see a a tab at the top for Shadow Complex right next to Fortnite and Unreal Tournament. Press the install button and you're good to go.
For reference, the minimum requirements are:
- CPU: Intel i5/AMD A4
- System RAM: 4GB
- Video Card: Nvidia GT 540 1GB/AMD 5550 1GB
- DirectX 11