There are few games out there today that enjoy as faithful a fanbase as Counter-Strike. With each new iteration that comes along, it's almost implied that most people will move on over. Today, Counter-Strike: Global Offensive regularly ranks #2 on Steam, with an incredible 590,000 players currently in-game as of the time of this posting.
There are reasons for the love of CS 1.6, though. Part of the draw is the fact that the graphics are weaker, which means it easier to spot your target amongst all of the scene noise. Actual game mechanics tend to be quite favored as well, even if some of them are tied to flaws.
Nonetheless, it's almost no surprise at all, given the strong fanbase, that someone out there managed to get CS 1.6 working on Android. That in itself might not sound too impressive, but consider this: the feat was done by a single person, and this is real code running on the device. It's not a remake, and it's not a stream.
Naturally, playing a game like Counter-Strike is not going to be ideal on a mobile device, but because Android supports many peripherals (assuming the device itself does), you could hook up a wireless mouse and keyboard to the device to make the experience a lot more enjoyable.
Feeling ambitious and want to give this version of CS a go? You can hit up Alibek Omarov's GitHub page below and snag it. It looks like it will be left up to you to actually get the game installed, though, as instructions don't seem to be given, and neither is an APK. This is some definite hands-on work, but the payoff could be worth it.