I have been a fan of the Call of Duty franchise for years, which only grew with the release of Black Ops 2 in 2012. Since then, my interest has expanded to numerous other video games, but Call of Duty always has a special place in my heart. After the release of Ghosts and the addition of the advanced movement systems beginning in Advanced Warfare, people have taken the franchise less seriously or come to dislike it. The release of World War II last year marked the return of boots on the ground combat, which is maintained in Black Ops 4.
In this pre-holiday review, I will go through all of the modes of the game (Multiplayer, Zombies, Blackout, and Specialist HQ) for a more comprehensive explanation of this game and its positives and negatives. Feel free to skip to the modes you are interested in, but be sure to check out my final thoughts at the end.

Multiplayer
Multiplayer fans, boots on the ground or otherwise, are in for some fun times in this iteration of the classic mode. With some returning and new features and maps, there are nostalgic elements for older fans and new ones to spice up the mix.
The Specialist system returns from Black Ops 3, with some returning characters and new phases. For those who aren’t familiar with the Specialists, here is a brief explanation: At the beginning of a match, you select one of 10 Specialists, each with a unique look and a powerful weapon. The system of their weapons and abilities have been greatly tuned, though, to better fit the time period in which the game is set. For the most part, the returning Specialists abilities are the same, though they have all gained a secondary ability. Ruin, for example, retains his Grav Slam (a renamed Gravity Spikes) from Black Ops 3, but now he also has a grapple ability for greater mobility on a cooldown. Most of these abilities are very useful and practical, though Specialists like Ajax with his Ballistic Shield need a little bit of tuning, which I’m sure will come soon. In the Create a Class menu, you can also select a special issue Equipment, replacing the special second ability from each Specialist, which can be applied to any Specialist.
The healing mechanic in this game is entirely different from that of previous games; there is a quick use healing item on cooldown rather than automatic healing. This sounds like a change for the worse, but from personal experience it adds more flexibility and tactical decision to the healing process. The cooldown for this healing can also be reduced by equipping Stim Shot in the Gear section (a new section that has several useful items for picking) of the Create a Class.
For those who stick to playing older games in the series, there are remakes of classic maps like Slums, Firing Range, Jungle, and Summit, and, before the end of November, a new iteration of Nuketown. The gamemode itself is well paced and easy to pick up, while still fun for veteran players.

Zombies
Treyarch made Zombies a main focus for sales campaigns for Black Ops 4, and justifiably so with the popularity the mode has gained. Upon buying the game, it gives players 3 distinct maps: two from the new Chaos storyline, and one featuring the Primis characters introduced in Origins in Black Ops 2. Black Ops Pass owners are also granted a fourth map, Classified, which features the Ultimis characters from the original introduction of Zombies in World at War. This game makes some controversial changes to gameplay and reimagines some classic, fan-favorite maps.
The Chaos maps, IX and Voyage of Despair, wonderfully introduce players to the new characters in interesting historical locales, with IX in a gladiatorial arena and Voyage of Despair on the sinking RMS Titanic. IX is an easy map to pick up and fun for play; the map layout is straightforward and the mechanics are easy to learn for beginners. Voyage of Despair is a huge map with many close-quarters corridors. Though the map design and mechanics are slightly more complicated, it is still accessible, after some practice, to all who take the time to learn these intricacies.
The two other maps, Blood of the Dead for everyone and Classified for Black Ops Pass owners, reimagine maps from previous games. Blood of the Dead is a remake of the fan-favorite Mob of the Dead from Black Ops 2. But this time, the Origins characters travel through an expanded version of the original map and, with the return of such features as the Hell’s Retriever and the Golden Spork, create nostalgia. New features like the Spirit Shield and the Magmagat were also added to create some differentiation. Classified is a remake of Five from Black Ops 1 featuring the original cast of Zombies characters rather than those in the original map. This map reinvents the original map well, adds features like the shield to make gameplay slightly easier, and changes certain aspects of the map to add some interesting storyline points.
There are also a number of gameplay changes to Zombies. Classic perks such as Juggernog, Speed Cola, and Double Tapp have been removed.  According to Jason Blundell, these were necessities that restricted choice in perk selection. This led to numerous new perks that have been added, along with the new modifier, on the fourth perk in your loadout, which activates when one purchases all four perks in the game. In this game one also selects which four perks are available to purchase in the map (on a player to player basis). The player can also choose the specialist weapons, starting weapon, and equipment.
The new systems, replacing Gobblegums, are the Elixirs and Talismans. For those unfamiliar with the Gobblegum system from Black Ops 3, there were a series of five Gobblegums that the player could pick from in the pre-game lobby.  Some were consumable and some were the Classics (unlimited uses), that would allow you boosts when you got them in-game. They could be obtained from the gumball machine, which would give you a random one of your equipped Gobblegums. The Elixirs in this game work much the same way.  You select either Classic or consumable elixirs in the pre-game menu to be used in game, but in Black Ops 4 all you have to do is press the corresponding direction on the D-Pad to activate one.  Unusually they can only be used once a round. Talismans are one-use items you equip in the lobby that activate immediately upon loading into a game.  Some last the entire game and some give a temporary boost at the start.
Treyarch wanted to add more player options to this game, so they created a Casual mode and tutorial for more beginner or laid-back players.  Furthermore, there is Regular mode, the default for most players, and a Hardcore and Realistic mode with lower health and more advanced AI. There is also a new gamemode, Rush, where you enter the map and have to gain as many points as quickly as possible.  You can either compete or cooperate with your friends to survive short lockdowns in specific areas of the map. Everything in Rush, from perks to weapons to upgrades, are free, but the Mystery Box and Pack-a-Punches are restricted to 30 second cooldowns.

Blackout
In a departure from traditional Call of Duty layouts, Treyarch replaced the Campaign mode with two other modes: the smaller Specialist HQ and the more marketed Blackout. The map features classic locations from previous games, both Multiplayer and Zombies, and numerous weapons, attachments, perks, and easter eggs.
There is a large roster of new and classic unlockable characters.  You can unlock some of these characters simply by Blackout and leveling up, while other require finding special items and completing tasks. These item-specific characters range from the Specialists and Multiplayer to Reznov and Mason from previous games to Richtofen and Scarlett from Zombies. All of the character challenges have become available at this point, though some are definitely more difficult to complete than others.
Blackout takes an approach on the genre closer to PUBG than Fortnite, with no building mechanics, new weapon attachments, and no weapon rarity, which served as a major mechanic. There are land, air and sea vehicles available for use to outrun the “Collapse,” the closing circle that pushes remaining players together. There are also numerous Specialist abilities and weapons available for use as equipment (with very limited use), such as the Grappling Hook and Razor Wire.
Treyarch really tries to distinguish itself by incorporating zombies into Blackout. At certain locations, zombies will spawn occasionally.  When they are all killed, the Mystery Box is available for some good loot. These zombies can also drop weapons, healing materials, and Zombies character quest items, though it does take some valuable ammo to defeat them.
This gamemode has a lot of replayability and provides a lot of fun times with friends. But for all you Fortnite fans out there, it challenges even the best battle royale players.

Specialist HQ
Though Black Ops 4 does not feature a full-length, single-player campaign, Specialist HQ is actually an interesting and very different mode. This mode differs from a traditional campaign in the fact that it isn’t a story-driven gameplay experience. The gameplay itself is simple tutorials and practices, with story cutscenes and audio logs as rewards for completions. The story, though, is connected to the previous Black Ops stories (though much less so Black Ops 3). This mode is also good for those with little to no Multiplayer experience who want to better learn how each Specialist works and have some practice with each one.
From the first opening of the mode, you immediately become introduced to the story through a cutscene. Each Specialist then has a tutorial cutscene and a playthrough tutorial which give a basic idea of how each functions with some fun training and gameplay aspects thrown in. Then a cutscene appears pertaining to the origin story of the particular Specialist. This leads into “Skirmish,” a Multiplayer game mode against bots to practice some of the Specialist’s abilities, ending with a Black Ops storyline cutscene.
After playing through each Specialist for the first, a wide range of options bloom. Each Specialist has 3 stars of difficulty, which can be earned by completing the Skirmish again on a higher difficulty. There are also a number of challenges under the Story tab to complete for more audio logs to further the storyline. Fully completing all of the challenges takes a significant amount of time, though not quite as long as a traditional Campaign. While I won’t spoil the story, I will say that fans of the Black Ops 1 and 2 storylines will  definitely find interesting things, as well as some interesting implications for the story of Black Ops 4 and subsequent games in the series.

Final Information and Thoughts
There is a lot to be said about this game, and not all of the aspects, positive or negative, were listed in the above summaries. 
Multiplayer functions are pretty good. I personally have experienced only one or two crashes, and those only occurred shortly after release and seem to have been corrected at this point. The games aren’t usually too long and there is something for everyone. As of now, though, there are no party games. Gun game is a limited time exception, but it isn’t even available in custom games. Some of the most fun my friends and I have had were in Gun Game and Sticks and Stones in Black Ops 2, and it could only make the game better to add party games. 
Zombies is a solid game mode, with options for players of all experience levels. The Easter Eggs are difficult but attainable, and setting up and playing in general is easy for casual games. There is, however, a problem with game crashes in the Zombies mode. I personally have experienced several crashes in the lobby and with games just messing around. Many in the high round community are experiencing crashes on rounds nowhere near where they are capable of achieving because the game isn’t currently stable enough to handle that. Hopefully this will be fixed soon, with many Easter Egg crashes and other crashes already fixed or on the radar. Treyarch has recently implemented an in game system to track crashes and the causes of them, so they will be more easily to track and fix.
Blackout is a fun gamemode with plenty of nostalgia for old players and fun gameplay moments for everyone. The mode is very stable. Personally, my game has only crashed once on this mode shortly after release. There are numerous challenges to complete and characters to unlock, which usually require playing lots of Blackout and placing well.
While many, including myself, wish there was a Campaign mode, after playing through the Specialist HQ I can honestly say that I enjoyed it. The story is very well done, though unlocking the later challenges such as getting all 10 silver and all 10 gold stars can get monotonous. For those interested in the stories of Black Ops 1 and 2, as well as the Specialists of Black Ops 3 and 4, you should definitely play through this mode at some point.  Whether you grind through it or go one game at a time, it is a very interesting experience.
The main problem, besides the crashing incidents, is the microtransactions. Currently they cost $5 in the Laboratory for the best odds of good elixir and talismans and nearly $200 to buy through all 200 tiers of the Black Market. This iteration of the Black Market is similar to Battle Pass in Fortnite, though it is 200 tiers and you do not have to purchase an upgrade to unlock better rewards.  While I have reluctantly come to expect these microtransactions, the price seems unreasonable in this game, and hopefully it will be fixed soon. 
Overall, the game is solid and has a lot to offer for players across the board. The Multiplayer, Zombies, and Blackout modes offer plenty of fun opportunities for months to come, with only more to come as the downloadable content is released within the next year or so. This seems like it is going to be a big year for Treyarch and the Call of Duty franchise as a whole, taking risks on new modes and pushing the boundaries on the improvement and interest in their returning fan-favorites.