The traditional structure of a essay is "Tell them what you're going to say, then say it, then tell them what you said." The introduction and the conclusion are both overviews that include the main points you are making. The introduction prepares the readers for those points, the conclusion reminds the reader of what they were. So it's hard to judge your ending without knowing your beginning.
The conclusion, the "peroration," can be less formal and a little more emotional that what has gone before. You've used facts and logic earlier. The conclusion is a time to do a little "selling."
If you, yourself, have used ESL games in a classroom, I would go ahead and use personal language here--the pronouns "I" and "me"--unless your teacher has told you not to.
Your main point is that you think games should be used. You think they are valuable. That's the most important point, so that should be the last thing you say. The qualifications--high quality, related to the theme, fun--come earlier.
Taking some guesses, and re-writing your paragraph, here's one idea:
"First, the game needs to be relevant to the lesson. If you are teaching prepositions the game must be about prepositions. Second, the game must be fun. If the game isn't fun, it won't work just because it is 'a game.' Good games are valuable in the classroom. I use games, I like them, and I recommend them."