After replaying most of the AC games over the past few months returning to AC1 was an interesting experience. Some parts upon replaying it again I expected but other parts surprised me. The story, parkour system, music and atmosphere and brisk pacing of the game is what I found fascinating upon coming back to the game over a decade later. AC1 isn't a game I consider to be amazingly designed, it has just enough going on from a moment to moment gameplay standpoint with an engaging story that it was enjoyable.
The story I have a soft spot for since it was my first introduction to stories with philosophical themes and questions. With that said, the only big issues with it is the begginning, ending and some of the plot twists. The first issue probably going to turn away many since it starts with Altair killing an innocent old man and disregarding a creed that he seemingly followed for a long time. What lead to the disillusion of it? What lead to Altair's arrogance? The game never answers this. However, if you can get past this, the story from here and out is full of intrigue and thought provoking moments.
The dialogue Altair has with his assassination targets and the Brotherhood he serves is the biggest highlight of the story. In how with each target Altair kills, he starts to question if he is doing the right thing. His targets speak of good and noble intentions where his allies and by extension master Al Muliam often reassures that what they say are lies and misdirection. Altair and by extension the player however are still not 100% sure. What also helps is that at the start of the story after the inciding incident, the Assassin Brotherhood treats him with scorn but he slowly earns their respect with each assassination in the various cities. Al Muliam would often test his conviction to the cause with cryptic riddles and questions. The best part is that all of these dialogue sequences are never overly long and to the point.
There are some questionable plot twists like why did Altair take so long to figure out the men he was sent to kill where connected due to them being Templars and was Al Muliam always evil or did he go through a heel turn? The lack of backstory can take the idea of Star Wars logic a little too far. The ending is also very anti climatic and doesn't provide much closure.
Atmosphere and music is also quite good. With the Jerusalem, Arce and Damascus ambient songs giving a lot of character. The gritty and grimy look of Arce is contrasted the more hopeful and upbeat Jerusalem both accompanying by music that work in tandem with each other to give an immpecable vibe.
The gameplay is interesting in that it has a mission system that is infamous for being "repetitive" but it is accompanied with at the time a novel climbing and free running system.
However the fulcrum of what makes AC1's gameplay solid is how it follows the idea of, "it's over before you know it". Every mission like pickpocketing, eavesdroping and interrogating are over in less than a minute. Climbing up the towers to find them is also quick. Side missions where you need to rescue civilians are also brisk. You climb, do a quick mission then climb some more. This free running system is intuitive enough it can be enjoyable and immersive climbing up such tall structures. It also helps that hidespots are on rooftops so when chased by guards, it's still encouraged to free run and use the roofs.
The act of the assassinations themselves can also be over and done with fast. In a game like Hitman, much of the gameplay in the levels are spent trying to get up close and then quietly killing your target. In AC1, most of the legwork of getting close to the target is done in the open world so the actual kill can be down through semi efficent infiltration or getting caught and quickly getting the kill before the target can draw his sword and it becomes an actual duel and by extension brawl. It ends in a chase accompanied by an amazing chase theme. Hidespots are plentiful and breaking line of sight is not difficult so it adds to the brevity of the game's challenge.
The assassinations towards the end of the game do a good job at throwing more geniune shakeups to the game.
It's not all amazing since one big issue with the game is the terrible AI especially the furthur you get into the game since guards become more aware of Altair's presence and more trigger happy. A massive strength the game has that there never any extended sections where you aren't allowed to be seen or it's a game over so the devs are aware of their enemy AI shortcomings.
Combat is decent and swift. It's not counter spamming or getting one kill means leads to insta kills. Enemies can do heavy attacks which can't be reliably be countered and partner that with weaker enemies encourages defense and offensive. One heavy attack can't kill you but multiple can level your life bar.
Overall, the brisk gameplay pace, the amazing animations, dialogue and music carries AC1 even if the terrible enemy AI and rather simplistic mission and by extension gameplay structure can reveal the illusion a little too much.