The Sentinel Comics rpg is based off of a superhero card game. Presumably like the card game, it has the conceit of being based on a comic book universe. Mock covers are shown and issue numbers thrown around, etc. It's art is a bit cartoony, which seems to be kind of a trend in supers rpgs (ICONS is the same way).
The game is best characterized as a somewhat narrativist, superhero combat simulator. "Somewhat narrativist" meaning that it is built to emulate superhero stories not model a world which has superheroes, and that some things that might be specified in other games are left loose, or a lot of different fictional descriptions might fit the same basic mechanics. I say "combat simulator" meaning that it, like 4e D&D, seems geared toward combats. Almost all of it's abilities are aimed in that direction and it's bells and whistles for players to engage with are combat oriented. Unlike 4e, combat really isn't tactical; there is no strict movements or battle maps. I guess you could say combat most reflects its card game roots.
I find a lot of things about the system compelling. In many ways, it seems a refinement of some of the concepts in Marvel Heroic Roleplaying (at least one of the same designers worked on both). It's basic mechanic is make a dice pool from a Power, Quality, and status (more on this soon), and take the middle number. It's pretty easy and quick.
Status follows a color-coded system called GYRO (Green, Yellow, Red, and Out). Advancing from one color to the next "unlocks" new abilities specific to your character. I think this models pretty well something seen in comics, where Spider-Man does usually seem to have the proportional strength of a spider until he really needs to have the proportional strength of a spider. The Hulk gets angrier and stronger the longer he fights, etc.
All actions are subsumed into four categories: Attack, Overcome, Boost/Hinder, Defend. Overcome is probably the broadest of these. It's used for most sorts of story obstacles from finding information to disarming a bomb. It's also the main one that gets leaned on in none combat situations. Success at it is graded with narrative consequences: twists of the major or minor variety, than are similar to 2d20 system Complications. Sentinel Comics only having subsystems for combat is one of its deficits for me, though admittedly the Overcome action works in a more "cinematic" (or comic book) way than a bunch of skill challenges or the like.
My biggest complaint with it is character creation. It's kind of a mini-game onto itself and can be done Guided (random die roll), Constructed (choosing the options you could have rolled), or then for modelling characters, just picking and choosing individual abilities, which would be the hardest of the three. Every step gives you certain options and dice types to distribute to those options. It takes a longer time than I would like and requires a lot of flipping back and forth in the book, without even giving you the freedom that other "complicated character generation" supers games like Champions or Mutants & Masterminds. It's easier to tolerate an extended character generation to get exactly the sort of character you want, but Sentinel Comics rpg is an exercise in making compromises, some of which seem arbitrary.
Ending on my big complaint perhaps makes my review seem more negative than I intend. With two sessions in, I feel like the game plays pretty well at the table. It would be great for pregens and a con game. I'm less sold on it, as yet, for a longterm campaign.
