The very first of the Heisei Rider series, Kamen Rider Kuuga. This was the first KR series I tried to get into, but I couldn't really enjoy it from my initial impressions. A while later, I tried getting into it again.
it is awesome. Is it an absolutely perfect masterpiece none of the other Heisei series have matched? No, but it's a damn good series in its own right and a perfect way to start off the Heisei era of KR.
The story is rather simple: The Grongi are a race of monsters that partake in the Gegeru, a game that involves killing the Linto, AKA humans. Godai Yuusuke gains a mysterious belt through some strange circumstances which absorbs into his body, allowing him to transform into the being known as Kuuga, who sealed the Grongi away long ago. There are a few twists and turns later on, and the story remains interesting.
The part that really grabs you about Kuuga is the characters. Is Godai a sue? Sort of. I can't really deny any sue accusations about him, but I will say this: He isn't an annoying
sue. It's not like, say, Decade, where the sue protagonist completely irritated the hell out of me. Godai was an overall likable dude, and his sheer niceness served as an antithesis to the Grongi's idea that humans are all driven to destruction, (minor spoilers there) making him a somewhat justified
sue. The other supporting cast are all well developed for the most part, and their depth surprised me at time. I didn't expect the silly foreign guy who randomly spoke in english to become so likable.
Of course, it IS Kamen Rider, so I have to talk about the fights/designs/awesome parts. Godai is a GIGANTIC BADASS
and the action really picks up after episode 4, along with the special effects sorta kinda. They go for a lot more insta-changes rather than the hilariously cheesy looking henshin type from episode 2 after a while, so it looks better. The Kuuga suit is simple, yet effective, and the fights aren't as explosion laden as later Heisei series, but there's a sense of raw brutality that's quite satisfying.
In summation, Kamen Rider Kuuga is a fantastically written, well developed show, and well worth a look if you're interested.
Also, YOU JUST LOST THE GEGERU