-TIPS-
The key factor to making one I would say, is to not just play Kirby games, but understand them from a technical standpoint. Many fan-games try to replicate the feel, but very few get it right. Speed, jump height, latency of inputs... All those and many more are quite important. You can even extend your playtime to various platformers & fighting games, it all shares that DNA!

Next, arm yourself with a lot of discipline & motivation. This is true for most projects, but Kirby in particular is quite complex and demanding. All of the different Copy Abilities and player states require a certain degree of flexibility to make it all work. It needs time & effort to get it all right!

Lastly for tips, this isn't a tutorial on how to make a game from scratch, but you should have basic notions all figured out for this type of game. Take your time, start with experimentation, while watching a tutorial or two when needed. One day, regardless if it's Kirby or not, you're going to be proud of what you made!

-MY EXPERIENCE-
...Has been really positive so far! I started this project, because I was a bit disappointed that Kirby and The Forgotten Land wasn't as open as I wanted it for the series' true 3D debut. I've wanted a game like Amazing Mirror since it came out (18 years... ouch). Coincidentally, I needed a challenge as a game developer, so I've set out to make that game myself. Made a basic prototype in a month, released it here on Game Jolt, and then people started coming over quicker than I ever expected. Now that I've got almost 150 people (and maybe more!) who are excited for this game of mine, bring the kind of motivation to see things through!

I plan not to make the best Kirby fan-game, don't get me wrong... I want simply to create the experience I've always wanted with this series and sharing it with you all. Something that even HAL wouldn't dare making, a relic of the past, at the same time, a door leading to the future. Alternative possibility now taken shape.

I hope you're looking forward to it as much as I do!