Now, there's not often that I will recommend a game mere days after I've bought it.
It's even less often, comes a game that I feel almost compelled to buy it for all of my friends, so they can enjoy it as I have.

I bought 20XX during the last time it was on sale, and in doing so, I also bought it for 5 of my friends.
And I haven't regretted it a single moment.

More than 3 days of playtime already logged and not planning on stopping anytime soon, 20XX is a masterpiece in the Roguelike genre, and Jump 'N Shoot platformers too.

I can appreciate the cartoonish artstyle that harkens back to the spiritual predecessors, not to mention it looks well polished too.
The sound quality is top-notch, from the shot sounds to the death sounds, everything has an organic feel that audiophiles will certainly appreciate.
The platforming is great too, nothing feels too out of place, the randomized aspect can lead to crazy, unique ways to find your way through the level while not feeling clunky. Mechanically, the game is as sound as Megaman X with a few added bonuses.
Each character feels unique, and even if the default characters are obviously inspired by Megaman (Z)X protagonists, they are their own characters.

So far, the game looks great, feels great, and sounds great. It accomplishes everything a Roguelike wants, while also incorporating that Jump 'N Shoot feel without sacrificing from either area. It's an absolutely wonderful combination of each, and feels at home in both worlds while separating from similar games. Where are the negatives?

It is somewhat buggy, for a game of this level of polish to have bugs is almost disappointing, if they were anything gamebreaking at least. Most of the bugs are minor, although there are crash bugs (like the Endless Online Co-Op bug), most, if not all, of the bugs do not remotely affect gameplay.

20XX gets a 9.25/10 from me. It's not perfect, but it doesn't have to be perfect to set the bar pretty high for everything else that wants to follow in its footsteps.