Well I just got done playing Begone for the last 6 hours. It is a browser based FPS, which means you don't have to download it to play it - my favorite kind of game! I am not that good yet but getting better. One thing I learned today, which you should do if your new, is go into your options and set the sight to "Stay". It makes aiming a lot easier! If you want full screen you can just hit "F". It's at www.nplay.com/BeGone/. It uses the Unity player so you might have to allow it to install the plug-in. Unity is safe so don't worry. Also, if you like using a headset and mic to communicate with your teammates, get RaidCall. It is low-latency, free and is used by gamers for all kinds of games. It's at raidcall.com

Never heard of either before, just played it for a few rounds and liked it.

It's far from unique as it's basically a basic version of Counter-Strike but considering that it doesn't require any installs, not a bad alternative in contrast to something like Combat Arms. As for Raidcall, seems interesting. I have used GSC in the past which appears to be similar except I think it's more bloated.