Play in I Love the Corps is based around the abilities that characters, Friendlies and Hostiles possess and using these abilities to defeat other combatants, resist Horrors and avoid Hazards.
The game is a story that is broken into narrative and action scenes, which are broken down into beats: moments of drama and excitement within a scene.
In each beat, you can use an active and passive ability to dictate dramatic actions; active abilities take the ability's score and then add a single D6 roll and any situational bonuses to determine the total, whilst passive abilities add the score to a static number (which is 3 during a narrative scene, 1 during an action scene).
Whilst abilities in general reflect the character's learned skills and natural capabilities, an active ability represents that skill combined with extra effort. A passive ability during a narrative scene represents how a character shows their know-how with time and no complications, whilst in an action scene, it is an action that requires little thought or focus.
In either scene, often trying an ability for the first time won't bring total success; you can't just hack into a computer in five seconds unless you are the absolute best. But if you start hacking into the system successfully, further concentrating will let you continue to amass what are called success levels until you succeed. The more success levels you have, the better; and if you have negative success levels... pray you have strong armour.
Each character has a lethal, non-lethal, psychology and sensory status to determine their physical and mental resilience. All abilities can be used against each other to create success levels, which are then reduced by the target's Hardass or Stay Frosty scores, to see what is added to the status. When that status hits a threshold, you're in trouble!
A compromised marine could be concussed or bleeding out, finding actions more difficult, and a neutralised marine is either knocked out, instantly killed or on their very last legs, refusing to go down but suffering horrific physical trauma. If you are Freaking Out, it is harder to do things from the panic, and if you are Losing It, then you do something crazy for the scene.
In order to survive, marines are helped massively by earning themselves GLORY! If you create impressive moments of role play and story advancement, you earn Glory Points to spend later to aid your character. And for each Glory Point, you get a Fortune Point, the only way to improve your character.