Video games based on Gundam have a terrible reputation, and it while it is not entirely undeserved, there are a great deal that goes completely overlooked. There are a lot of games that are awful, a lot that might be good for fans of certain genres, and some that are incredibly satisfying for fans of the series. As a fan of the franchise, I can understand how readers may not consider me a reliable source, but there are good Gundam games, and it bothers me that people seem to completely dismiss any game with the Gundam on it. This is by no means a complete guide, but I think it covers a good deal of important titles.
I feel that before I get started I should clear up some common misconceptions about Gundam in general. Gundam fans are not necessarily anime fans, and in many cases, including my own, Gundam fans are generally just fans of science fiction. Anime is a medium for storytelling, not a genre, and if the look of '80s anime is a turn off I suggest giving the Mobile Suit Gundam novel a try. Also, in the US, the only association most people have with Gundam is Gundam Wing, which is set in a separate time line than the majority of the franchise and does not necessarily represent the content of the franchise as a whole. Gundam is about war stories, political conflicts, moral ambiguity, personal responsibility, and of course pilots killing each other in large robotic war machines.
Anyway, over the years there have been a great deal of Gundam games released over the last thirty or so years, which is to be expected considering that it is owned by Bandai, a company that has made a lot of games. While Z-Gundam: Hot Scramble for the Famicom wasn't the first Gundam game, it was one of the earliest, and it is terrible. In theory, a game in which the player can fly around as a plane then transform into a bipedal mech is awesome, but somehow no one in the NES games could make it work. Hot Scramble isn't fun, and Formation Z, a remarkably similar game that isn't actually related to it in any way.
Bandai actually figured out early on a type of game that works well for Gundam, and that is the turn-based military strategy game. Though the genre only became popular in the US with the Advance Wars games, it was actually quite prolific in Japan starting with the Famicom. There are quite a few SD Gundam games for the Famicom, and though they aren't mind-blowing in any way, they are solid strategy games and there have been a lot of good games in the series since. Related to this is the massively popular, again only in Japan, Super Robot Wars series, which features Gundam and a bunch of other mecha series in some of the most hardcore turn-based strategy games out there. I suggest that people who enjoyed Advance Wars check out one of the Super Robot Taisen: Original Generation games for GBA, though they might be tough to find and don't actually contain any Gundam stuff, the way the game plays is there.
One genre that Gundam was inevitably going to intersect with is fighting games, which has met with mixed results. The Super Famicom hosted a G Gundam game, Kidou Butoden G-Gundam, and a Gundam Wing game, Shin Kidou Senshi Gundam W: Endless Duel. Neither game is very good, but are decent Street Fighter 2 knockoffs with some pretty good sprites. I do wonder why giant mechs have “breath” animations though. The PS1 was better off with the Gundam Battle Assault games. They were greatly differentiated from other fighting games with different systems and a unique animation style. They aren't great in terms of well-built fighting games, but they are pretty fun.
Since the advent of 3D graphics, most Gundam games have been third-person action games. This has been met with varying degrees of success, but it also the era when the popularity of Gundam in the US meant that many titles actually got localized. I don't really have an experience with most of the games from this time, so I can't say what is a good and what is bad, but I can say that there are a lot available for the PS2. After the popularity faded, the Gundam Battle series was released annually for a while in Japan on the PSP. These are my favorite Gundam games because there are tons of things for dedicated fans like me, such as hundreds of different mechs, a great deal the franchise's memorable moments, solid controls, fun combat, and the ability to tune the stats of each mobile suit. I highly recommend the final PSP title, Gundam Battle Universe, at least to fellow Gundam fans with a PSP that can play Japanese PSP games. It was also ported to 3DS under the name Gundam the 3D Battle, but presently that would require a Japanese 3DS to play.
Lately the only Gundam games that seem to come over to North America are the Dynasty Warriors Gundam games. I really did try to like these games, but frankly they just annoy me. I appreciate the amount of effort that went into the fan service, and there are a good deal playable mobile suits from different shows, but the way the game plays annoys me. Frankly, the game is too much Dynasty Warriors and not enough Gundam. It drives me nuts that the game is so focused on melee combat in spite of the fact there are tons of mechs with laser weaponry running around. It just doesn't make sense to me. On the opposite hand, there are the Gundam Vs. games which strike a good balance between ranged and melee combat and generally have a really fun combat system. They are just really solid competitive arcade games, which I guess is to be expected from a game developed by Capcom.
The general quality of Gundam games is frustrating, because in theory they should be awesome. Piloting big mechs and blowing other big mechs up should be something that lends itself to fun action games. But somehow Bandai ends up with stuff like Mobile Suit Gundam: Crossfire. It's just sad that it so rarely lives up to the potential. Still, there are some solid action games out there. There are other hard-to-classify games like Ghiren's Greed and Gundam Side Story 0079: Rise from the Ashes. Most importantly, there are good Gundam games out there, especially if you are a fan of turn-based strategy.