The Amiga had a preemptive 32-bit multitasking operating system, DMA audio and a high-performance custom chipset for graphics and DMA.
Windows didn't have a 32-bit preemptive kernel before 1995 and MacOS users even had to wait until 2001 (MacOS X).
And how does that have anything to do with the computer itself?!
Besides, most (all?) Amiga games were booted on the bare metal, which means no OS, which means no kernel to speak of.
Just a comparision, here are some typical X68000 games:
...
And here is a demo that already runs on an original A500:
A DEMO?! Really? Come on, you can't be serious! Demos are programming masterpieces that enhusiasts build to show off their absolute mastery of the system and their coding prowess. A demo does not show off the capabilities of a system. It shows off the capabilities of its creator.
To drive home the point... This here is a C64 DEMO:
..while this is a typical c64 game demonstrative of the hardware's capabilities in the hands of a good programmer:
As for which system is more powerful, you should read the specs. And the x68000 blows the Amiga far out of the water when it comes to specs, in sound channels, in number of sprites, in screen resolution, in processor speed, in any actual metric possible.
It's okay to be an Amiga fanboy, but don't be crazy.