As specified by Kixeye, "These are the minimum system requirements to ensure a quality play experience. If your system does not meet these requirements, you may encounter technical issues.". So technical issues? Like bugs?
So here's their specs:
-3GHz or faster processor (Core Duo 1.33 GHz or faster processor for Mac)
-Windows XP, Windows Vista or Windows 7, patched and updated to the latest version or Mac OS 10.6 and above
-Google Chrome (recommended browser for best gaming experience), Mozilla Firefox 9.0
and above, Internet Explorer 8.0 and above, Safari 5.0 and above (web browser needs to have default settings and no add-ons or plug-ins installed)
-1 GB RAM
-1 GB of free hard disk space
-Latest Adobe Flash (Find Out Your Version and update it at http://helpx.adobe.com/flash-player.html)
-1024 x 768 or larger screen resolution
For Network or Internet Connection here's the specs:
-Broadband Internet service (Cable, DSL, fiberoptic, etc.)
-Any router or firewall used on the network should use default settings to ensure reliable connectivity.
Conclusion
If you don't have the minimum specs, no one can stop you as long as you still enjoy the game (even if it lags like hell and you can't even bank your resources). But for the lag, no matter what system you're using you'll always experience it even if you have your own Gaming Rig/PC. The system specs are low but it's already weird enough to have system specs for a FLASH game. But if a game is full of bugs, It's not because players are playing their game in a slow PC but it's because your game is not well coded. In the end, It's still your choice to play the game whether it's because the game is buggy or you don't reach the minimum specs to play it.