Pfft, your mech houses your mom's soul? well MY mech is copiloted by Chthulu!
Touchstones: Armored Core, General Mech Media
Genre: Mecha, Tactics game
What is this game?: Lancer is a tactical TTRPG focused on mechs, and the folks piloting them, with a sturdy "Gameplay over Realism" mentality to its game design
How's the gameplay?: Lancer is a tactical RPG using primarily d20s for attack rolls and other problem solving, it's primarily based on the tactical combat rules of Dungeons and Dragons 4th edition, however it is mostly its own thing, with new mechanics, simple but fun character creation, and a high focus on quick and aggressive combat rather than lengthy and Defensive combat. in effect imagine character creation as going to a subway (of mech parts) and picking your ingredients, with a mech's frame being your choice of bread, and combat as an SRPG of your choosing but everyone is in giant mechs
What's the setting (If any) like?: Lancer throws you into a world where mankind's either solved, or is close to solving, most of the issues back on earth... too bad we also colonized other planets 10k years ago! Now, while Earth thrives, planets outside of it struggle with poverty, imperialism, dictatorships, and human and non-human rights issues, Earth tries its best to help, but they're stretched very thin. Lancer also has many small details to its setting that are way too in-depth to get into right now, but a major one is the existance of non-human people, eldritch beings strapped to computers in order to create effective and fully sentient artificial intelligence
What's the tone?: Lancer's tone is generally speaking, hopeful. Empires are mighty, but there are people fighting, and they will be toppled, mankind's horrors have attempted to wipe out entire species, but survivors remain, and secretly thrive. While there is some doom and gloom and grimdark stuff, especially with how the highly unethical and wicked corporations are treated as necessary evils for enterprising pilots, but overall lancer is a setting where no matter how bad things get, there will always be hope
Session length: A few hours, it depends on how mean your GM is, generally speaking however combat heavy sessions will only run you around 2-3 hours, with RP sprinkled in between
Number of Players: I generally like to recommend around 4 or more, but I'm sure you can do it with less
Malleability: While lancer's mechanics are pretty hardset in its setting, the existance of Beacon RPG and how at its core its very much a Lancer hack does show that Lancer can be hacked into differing settings, a very popular one I've seen is Magical Girl Lancer.
Resources: Lancer's primary resource is Comp/Con, it effectively serves as a do everything tool for lancer, allowing you to manage characters, encounter, and homebrew, while also having a very slick and easy to use UI
Lancer also has many pre-made modules, of... varying quality, Siren's song and Solstice rain are pretty good, Wallflower is very good but the encounters are of mixed quality, and it's not great for introducing people to the game in my experience
Homebrew is also fairly popular, new frames, NPC types, Bonds, and modules are all pretty popular, my personal favorite being Field Guide to Suldan and Field Guide to Iridia, I also enjoy Field Guide to Liminal Spaces though that one's a bit on the "Be Very Careful" side
Overall, lancer is effectively THE indie ttrpg, being quality, fun, and affordable, with the core rulebook being 100% free if you just wish to see the player-side content, it's a great time, and everyone who's interested in the indie ttrpg scene should check it out at least once