I don't see it as a game but I do enjoy it, so in that sense it could be called fun. However, as a lot of other people have said, when money is involved, it also requires a level of seriousness.
I have two different sides when it comes to crypto. The first is the hoarder. I decide on a coin, based on my own research and usually because I like the tech and/or the team behind it. With these, I will keep them off exchanges and let them sit there in wallets. These are long-term investments and I am not bothered by day-to-day price fluctuations.
The second side is the day-trader and I do enjoy this part. However, I never trade with the coins I am collecting. If I do not care about the coin, then it is purely about money, so it is easier for me to buy & sell these. This is just what works for me, maybe other people are different. I am reasonably successful with trading although there is always room for improvement and I need to learn more about TA, at the moment I understand basic TA. The fun part definitely comes from selling at a nice profit, especially if a sell order goes through while I am asleep...
Although, as with everything in life, you win some, you lose some. Losses can make me angry sometimes, even really small ones, but I am learning to deal with this & just wait it out. What goes up must come down (and vice versa).
Lastly, I find crypto an excellent (and fun) way to save. I find it very difficult to save fiat money, it always gets spent somehow. But once I put money into crypto, it stays in crypto. Maybe the coin changes but the money stays put. I've only been actively trading since last June and already have more invested in crypto than I managed to save in fiat in the last 5 years - so I guess that speaks for itself...