Gun

The tactic I used which brought me fast success:
- Your first move with every first hand in the Game: All-In. In most cases at least one of your opponents calls. And if you win you reached two goals: 1. You have at least double that much chips than everyone else, who's still in game. 2. you eliminated at least one opponent. In case you lose and it was only a first hand you just start over.
- Cheat (with the 3rd card) as soon as you see a good possibility.
- Go All-In as much as possible. AI seems to drop in most cases. And even if you lose a hand - you will still stay in game because of the point I made above.

What I find useful as a tactic is to always RAISE your bet. This will typically show which AI has a good hand or not as they will either fold or CHECK your bet. Then based on your hand either continue with the hand or fold.

It can take some time to wear them down as you may only win the blinds, but the hands go pretty quick.

Note that these unlock as Missions as you progress through the game. After a couple of missions you will be able to do the Dodge City ones. Later on, I had just completed the Steamboat mission, you will be able to do all the Empire City missions.

Three in Dodge City (Alhambra Saloon) with "cheating" and three in Empire City (Hoodoo's Casino) without "cheating".

Utilizing the cheat as mentioned in the Achievement Guide for Insane Difficulty Complete, this achievement can be unlocked by only having to play just one game of Texas Hold 'em. Just follow the steps below:

1. Start a new game.
2. Activate the cheat using the instructions mentioned in the Achievement Guide for Insane Difficulty Complete.
3. Pause the game and select the 'Gun' option, followed by the 'Missions' option, followed by the 'Side' option, then select the '**SM Texas Hold Em' level and then load the last stage of this mission.
4. Play and win the card game using the tactics mentioned above.
5. Achievement unlocked.

This achievement is relatively easy, but a bit tedious. Firstly, the Game Gun should only require one full play through of the game -- on Easy difficulty. The "New Game+" code which can be found below will allow you to visit any mission in the entire game on any difficulty.

My personal suggestion with the Texas Holdem side missions is very simple. Use the cheat option wisely. They will never catch you cheating, but you will be able to have a pair of face cards very often, which will allow you to safely raise, or even go all in. It takes a bit of time, but I simply played through while watching television with my wife.