Some might argue that the first Assassin's Creed feels like a proof of concept, or glorified tech demo, or something along those lines. Looking at the game in retrospect, this is almost true.
As the very first game of its kind, the first entry to one of the largest franchises in the gaming industry definitely feels like its goal was to set the foundation of what was to come. In other words, setting up an ambitious and promising skeleton, just to see how to put flesh to the bone in a more confident and clear way.
The game does feel skeletal in its ideas, it's a game filled with many concepts that feel exactly like so. Nothing but concepts.
But the basic groundwork that's being set here is honestly still some of the best Assassin's Creed content out there. The gameplay and storytelling is raw and still quite compelling, even though later games fleshed out and improved different aspects of this game EXPONENTIALLY.
The atmosphere and art direction is honestly still the best in the series. The environmental art design, the soundtrack, the lighting and color design is all on point.
Assassin's Creed, in retrospect, definitely feels like a large test run - or proof of concept, as some might say. But the foundation being set and the concepts that are introduced here are still some of the best the series has offered throughout its 15+ years of running and taking the industry by storm.
It has an enduring charm in its simplicity and the rawness of the game definitely makes it stand out compared to the franchise that would follow. Skeletal as it is, it's still an absolute treasure to play through.