Coin-op and F2P games also have similar beta testing phases.
All main features in the game lead to a good game experience, so the player keeps playing.
You have to keep in mind above all that, when beta testing a game, almost all game features must be in. If you test a game that's missing important features, the result you get will be completely different than if you test the same game when it's feature complete.
An example can better explain what I mean:
"This shooter game is boring," says the player. "The first 10 minutes are fine, but after a couple of hours playing it becomes repetitive."
Of course it's repetitive and boring! You haven't added the experience-based weapon unlocking system, so progression has no reward. The weapons improvements and weapon add-ons features are not in the game yet, so weapons are not too impressive at the moment.
The awards feature is still missing, so the player doesn't get performance feedback at the end of the match. There are still some unpolished features which can confuse or frustrate the player. The HUD still doesn't give all the information the player needs to have a good game experience. Spawn immunity doesn't have any feedback yet, so the player doesn't know about its existence... And so on.
You can't expect something to be fun when you know there are important missing elements. The game you want to test has to be almost complete, and ready to be tweaked if necessary.
Missing or unpolished features lead to frustration and the player leaving the game.
Normally, with video games, playtests are performed before the game is released. It's important to ensure that all in-game features are clear and players understand the gameplay. After beta testing is done, and once you have players' feedback, the final tweaks can be done. Then, the game can be considered finished. If you think it's necessary, you can organize another focus group just to ensure the game will provide perfect gameplay.
With coin-op games, we beta tested our games by placing a cabinet in a selected arcade for a few weeks. As I said before, you cannot beta test a game which is not almost feature complete, or not polished enough -- otherwise it can create confusion or frustration. In that case, players will simply stop playing the game and the cabinet won't get much traffic. If this happens, the solution is not too difficult: just tweak the game, and look for another arcade to attempt a new beta test.
With F2P games, beta testing conditions are similar to coin-op games, but you have to take into account that now the arcade is the entire world -- so you can't go looking for another world if you mess up your test. Well, you can limit the number of beta testers, but you only have one real opportunity to beta test the game before opening it to the entire world.
If the audience does not like the game (keeping in mind what I said about the quality of the first play experience), players will leave the game. And for the players who don't leave, making big changes can be dangerous, because people can easily react in a bad way to these changes -- just because the game is different than what they are used to, even if the changes you've applied have been good.
The most valuable information from the beta test phase is the player's first impression of the game. After the first week of play, people get used to playing your game, and, even without realizing it, they skip or avoid those uncomfortable or unfavorable situations. We said that the player gets "intoxicated" by the game, and, therefore, the results you get after a week get also "intoxicated". Remember, the most valuable info is always the first impression.
This article is just some thoughts based on my past experiences in the games industry. They were real sensations I had during the production of Freak Wars: Torrente Online 2, as I was constantly having deja vu moments of my splendid days working at Gaelco.
This article probably misses some similarities between these two types of games, and even similarities with other game types I didn't refer to, but maybe you can think of some and add them to the comments!
Special thanks to Abel Bascuñana for his guidance and help.