OK, so I'm going to start a list of corrections you may want to consider:
1.
"The Hunted (where one team escorts a weak, computer-controlled character as the other team tries to kill him)"
The person being Hunted is a player. They are forced to play as the Civilian class.
Robin Walker has stated in interviews that the TF2 Payload game mode was created to fix the problems in The Hunted game mode, such as having a bad Civilian player.
2.
"The game launched with six maps across three game modes"
The game launched with six maps across four game modes.
Those maps are:
- Attack/Defend: cp_dustbowl, cp_gravelpit
- Capture the Flag: ctf_2fort
- Control Points: cp_badlands, cp_granary
- Territory Control: tc_hydro
"Team Fortress 2 boasts a wealth of game modes, with lots of different maps for each one."
While this is true, it is also true that both TC and Medieval Attack/Defend only have one official map each.
3.
"Vintage is a commemorative quality for items crafted before the Mann-Conomy Update introduced the Mann Co. Store."
All items gotten before the Mann-Conomy Update were changed to vintage, not just ones that were crafted. This includes achievement items (introduced in The Gold Rush update), item drops (introduced in the Sniper vs. Spy update), and crafted items (introduced in The WAR update).
4.
"Another aspect of Team Fortress 2’s customization potential is the ability to create a “spray”."
This is not unique to Team Fortress 2. All of Valve's multiplayer games up through 2009's Left 4 Dead 2 support sprays. The first Valve multiplayer game to not support sprays was Portal 2.
Additionally, Valve's official TF2 servers have never allowed sprays; you need a community server for that.
5.
"Teams in Team Fortress 2 consist of twelve players"
...by default. Community servers can up the number of players to 16 players on a side. Competitive usually uses 6, 9 (one of each class), or (more recently) 4 player teams.
OK, enough corrections.
It may be worth mentioning that Blizzard's Overwatch has copied a lot of TF2's marketing... by introducing characters in videos, to having comics to explain the game's backstory, etc. I could understand not wanting to mention this though, as it would detract from the essay's primary subject.
On a side note, I vaguely remember my copy of Half-Life 1: Game of the Year edition having a Team Fortress 2: Brotherhood of Arms advertisement in it.
