Questions from potential future player

1. Solo play would be rough.  You'd have to manage at least three hands and play areas while paying attention to the villain and environment play areas.  And the game plays better with at least 4.  Have you considered getting the digital game instead?  That makes it much easier, and it's on a substantial sale right now.  (There's also a free demo of the digital game if you want to poke around at it.)
2. It varies.  If you're playing solo, a game could take a while.  About 30-60 minutes is about normal for a 4-player game in my experience.  Setup is negligible, less than 5 minutes.
3. Some villains, heroes, and environments are swingier than others.  The early villains in particular have That One Card that can wreck your day.  Longer games tend to be more consistent.
4. Oh my yes.  You can do well enough just looking at your own stuff, but there are a ton of interesting synergies.
5. Yes.  Some of the early, simple heroes in particular have a few cards that have a single, simple effect, but the vast majority of cards are much more interesting, and many heroes have nothing simple at all.
6. You can't really compare a fixed-deck game like Sentinels with deckbuilders like Aeon's End, Ascension, or Legendary.  It's superficially like Aeon's End but much more flavorful IMO, because no two heroes or villains have the same cards.  In Aeon's End, each character plays more or less the same but with some twists, while in Sentinels they're mostly more different than similar.  I'd say it's vaguely a cross between Aeon's End's general format and character panels, but sort of similar to Magic: The Gathering if you played only with preconstructed, non-overlapping decks.

1. Definitely still a great game solo, and allows for more powerful interactions and sacrifices.
2. Less than an hour, depending on the characters used.
3. Any card based game has some luck, but this has a ton of strategy
4. There are a ton of amazing cool combos and interactions
5. Lots of cool effects that are not just "do X damage"
6. Very different from Ascension.  Ascension has a lot more luck.  I like both, but I prefer the coop aspect of SotM.

All you’d be missing is Villains of the Multiverse, which imo is worth it for the environments, even if you don’t care about the villains.

1. For solo, I can’t say.

2. Again, can’t say for solo irl, but in the video game version they last about twenty minutes each, and over TTS with others they regularly last an hour and a half (for a rambunctious group), so... between those two?

3. This is a very thinky game.  It has a lot of luck of the draw, but since over 50% of the action is under the players’ control it’s not usually a crapshoot.

4. This game is all about the combo.

5. And all about the cool effects.

6. Nothing really comparable, I’m afraid.

Also, if you do decide to start playing, check out homebrew stuff like the Cauldron (a widely respected homebrew expansion).  It’s high quality.

1. Sentinels is my favorite game precisely because of how much I like to play it solo.  I think it was the first game I ever actually did play solo.  I primarily play digitally now, but I never really found it too difficult to keep track of things on the tabletop.  There are hp tokens as well as others, like damage modifiers, or can't play cards, etc and I suppose you could use counter dice too if you wanted, but I never have.

2. Setup is very fast.  Just shuffle a few decks (obviously that'll take a bit longer if you're shuffling them all yourself, but it's still much less to set up than a lot of games).  I'm not the best person to comment on game time, because pretty much everything I play takes longer than it says.  Excluding OblivAeon, the longest game of Sentinels I've played was 3 hours against the Ennead, but it was our first time facing them and we messed up the rules and thought you had to wait for all 9 to come out to defeat all of them, so it should have been shorter.  Typically it's more like between an hour or two, at least for me.

3. Since there is no rolling for damage or anything like that, Sentinels is pretty low on luck.  The only real source of luck is when certain cards will come up in a deck, whether that's for getting things your heroes need or how the villain is going to try to foil your plans.  There are also some effects that can blindly play the top or bottom card of a deck, so there's some luck there too, but it still boils down to what order did the cards get shuffled in.  And there are ways to mitigate that luck, like by letting your heroes draw extra cards to get through their deck faster or cards or powers that let you manipulate the villain or environment decks. There are definitely important decisions to make, like do I need to deal damage to take out this threat right now or can I spend my turn setting myself up to be more powerful later?  That's just one example, but there are plenty more.

4. Sentinels is VERY combo-y.  One of the coolest things is discovering how different heroes can interact with each other or even the villain or environment.  One of the most fun things about superhero battles in general is watching the heroes come up with creative ways to use their powers together (think Thor hitting Mjolnir off Cap's shield to create a giant shockwave or using his lightning to power up Iron Man) and that really comes through in this game.  You'll probably want to try discovering these combos for yourself, but there are also tons of guides written on here about all the things you can do with all the different heroes (as well as a very long "unexpected combinations" thread in the video game section).

5. I would say there are cool effects, but one of the coolest things to me is how well the effect usually matches the theme of the card.  For example, Sky-Scraper, a hero who can grow and shrink, has a card called Catch a Ride, which shows her in Tiny form crouched on the head of an arrow (a reference to a classic image of Ant-Man, which, sidenote, is another awesome thing about the game-all the comic book references).  The card has you select a hero other than yourself to deal some projectile damage to a target (maybe you pick the Wraith, because her targeting computer is boosting her projectile damage-yay combos!) and then Sky-Scraper deals that target some irreducible melee damage.  Even though that card's effect is essentially just "deal some damage to 1 target" you can easily imagine how you're shooting them with an arrow that Sky-Scraper rides on and then follows up with an accelerated punch to the face.

6. I haven't played any of the games you mentioned there, but I can compare it to Marvel Legendary, which is an apt comparison to make, since that's another superhero cardgame.  I've only played Marvel Legendary a couple times, but I didn't like it nearly as much as Sentinels.  For one thing, you're working together to defeat the villain, but it's technically not actually a cooperative game, because at the end, whoever killed the most bad guys is the actual winner.  I think some people might houserule to ignore that, but it just seems weird to me, like the designer didn't realize cooperative games could be a thing.  More importantly, in Marvel Legenday, you never feel like you're playing as a hero.  You can play some cards with Iron Man on them to do a thing, but it doesn't make you feel like Iron Man.  Playing as Benchmark in Sentinels and keeping track of all the different hardware systems and software running in your suit makes you feel like Iron Man.

It looks like the main thing you're missing is the hero variants (each hero has at least one and they change the hero's base power).  Depending on whether the copy of OblivAeon you're getting is just the OblivAeon box or everything from the OblivAeon kickstarter, you might also be missing some of the mini-expansions from that, namely Benchmark, Stuntman, and Void Guard.  Even if you are missing some things, you've got plenty to start.  I have everything now, but I didn't start out that way.  I hope other people here will have comments for you too, but I hope my thoughts were helpful and I'd like to say welcome to the community!

Sentinels does sound like the game for you. I would also add that if you are really into theme with your games than this will be great too. There is a lot of lore in this game and every character is built upon a theme, so every character you get is unique. There are lots of ways to go about the game and lots of ways people prefer to play. 

I will say, if you intend on playing solo (like I do almost exclusively) I highly recomend digital over physical, simply because it keeps track of the complicated interactions for you. Also the music is great.

The fellows from Munchkinland podcast have done a couple physical game playthroughs, you could listen to them to get a sense of the pacing.

I've never played physical, only digital.  The kind of heavy interaction, combo-heavy teams that I like to play would tend to involve a lot of shuffling and reshuffling, and I'm so much happier without the mess.  Also, the game saves at the end of every phase, so I can pull out my phone and play a little bit while in line at the bank or DMV and then put it away, which I do not recommend trying with a physical copy.  I will say that I learned the game on Ipad and I would probably find the level of text reading difficult to do on a phone screen alone, but now that I "get" it I have played new heroes (and the new Oblivaeon game mode) on my phone without playing on Ipad first.

On points 3-5 - people play the game very, very differently.  I care a lot about team construction and finding interesting/powerful/baroque combos, and so for me there's a ton of "game" that can happen while I'm away from the screen.  Other people really like to play random teams, or they play the weekly one-shots where the game hands you a team, and in these cases there may be few or no interesting synergies on offer, *or* you may be forced to find emergent combos during the game rather than relying on previously known synergies. 

I used to play solo.  Handelabra makes an app, but I use a different app, SotM Commander, which has always helped me.

Solo is, however, a lot easier on the Tablet than on the table, and I play often.

Hey, welcome to the forum :). I suspect my answers to your questions will be fairly similar to those above, but here we go...

1.) Solo play - I have played solo a bit on Tabletop Sim but it is more work than playing with someone else since you have to run every deck, and while the game can have only one player, you still need at least three heroes. It's most common for me to play with one other person, who controls two hero decks while I play one. I always control the villain and environment decks as well but as that's more of a matter of just reading out card text it's not exactly super-complicated ;). If you ar trying to singularly wrap your head around all the hero decks in play whilst controlling the villain and environment decks at the same time, however (especially if one or more of your heroes is one of the more complicated ones), and especially if you're new to the game and therefore don't know the decks that well to begin with, it may get a bit much. But you never know, maybe you'll enjoy it :D. If you have Tabletop Sim you can download the game there (and/or play it with other people online, plenty of us are usually up for that :D), and there is also an official Steam version for sale by a company called Handelabra.

2.) Game/setup time - Setup is quick, just shuffle all the decks you're gonna be using, give the right number of starting hp to each target (I favour dice for this but there are tokens you can use that come with the game),make sure you've gone any "Setup" text on the villain's character card, and you're good to go :). Game length on average I would say is around half an hour, but I've had games lasting anywhere from around ten minutes to about three hours. Four if you include Oblivaeon but that's a super-big-mega-fight so doesn't really "count" alongside the regular games ;).

3.) Planning versus luck - There can be issues with "luck of the cards", and some heroes can be more affected than this than others, plus some villains have horrible cards that you may not be able to do anything about, but learning the decks, knowing what might come up, and getting the hang of various setups and combos that can help with it are all valid tactics. You could play a game with exactly the same decks multiple times and have a different game each time thanks to the randomness of card order, but depending on the exact decks used the game may be harder/easier. Some villains are just outright easier to beat than others (because they don't mess with your stuff so much or dish out loads of damage all at once), and some environments can help/hinder the heroes/villains depending on where you're fighting. I've played this game hundreds and hundreds of times by now and I'm not fed up with it - sometimes I get my arse kicked in minutes but there is no villain that I have never beaten at least once. It just takes more work with some of them, that's all ;).

4.) Teamwork/Combos - Can you combo? Ohhhhh, yes! This is a big part of what makes the game so cool, the working together to do stuff. I'm not even all that interested in the superhero genre but I frigging love this game :D. Certain heroes really really like certain other heroes because they let them do their stuff so much better, and some heroes are just good at making everyone better - it's not just about smashing stuff till it dies. Yes, some heroes are dedicated to that and if you didn't go smashing bad guys you'd never win, but some heroes are more focused on support and letting their allies do more stuff, or be better at doing whatever it is they were already doing. With some heroes you may never do any damage from that deck the entire game and yet still be amazingly effective. For example, there is one hero whose thing is constructing robots which do the majority of her damage for her, but she can't play them during the "play a card" phase of her turn. But if it's someone else's turn, it doesn't matter, which means she loves anyone who can give her an out-of-turn card play and get set up that much quicker. And then she munches everything to death with a mini-army of raptor bots :D. Figuring out new combos you can do is a big part of the game, as is learning different ways to play each deck - you might have a setup you prefer on one hero and which you always aim for, but then see that hero played by someone else a completely different way which works just as well as your way. The promos for each hero (alternate character cards with different starting hp and base power) also change up the way their decks are played. If you don't have these cards you can just find their info online and jot it down on a piece of paper or something, since it's not like character cards need to ever be shuffled into the deck or anything.

5.) Cool effects - Think I covered this somewhat above, but yes, there are plenty of things that aren't just "I hit it" :D. Even effects like that can spawn loads of other effects, depending on what's in play - "I hit it, which kills it", "Okay, this card the villain has in play means they get to play another card 'cause you killed their thing...okay it's a one-shot that hits you for X damage and stops you dealing damage for a round", "Nope, I redirect it so the villain hits that minion of theirs that was gonna murder us next turn >:)". That's just an example but you get the idea :D. Sometimes even hitting a fellow hero is a good thing! But outside of that, there is plenty you can do outside of hitting - giving heroes extra actions (play/power/draw), stopping bad guys dealing damage, looking at the top/bottom card of various decks, playing the top/bottom card of various decks, putting out your own bots/constructs/devices which do a variety of stuff on your behalf, etc. Each hero is different enough that while plenty of them can do very similar things (there are plenty of powers that are "Deal one target 2 <type> damage", for example), it doesn't feel like any deck is the same as any other because all the other stuff they can do, and the way it combos with the rest of their deck as well as those of their fellow heroes, can vary greatly. Even between games played with that same deck!

6.) I have played Ascension, but Sentinels isn't much like that - it's co-op, for starters ;). Some of the card things can be considered similar to the way Powers can work in Spirit Island, I suppose, with the "I'm gonna do X...no wait, hang on, if I do Y instead and you do Z, we can stop those guys from doing that thing they were gonna do and then get set up for later", that kind of thing.

Welcome! You have a terrific user name, by the way. Muuuuulti-pass! :)

I think others have covered the topic pretty well, but I'll add: the primary way I play Sentinels is with my wife, each of us running 2 heroes. It works really well. I think the most mental load I had was playing Benchmark and Idealist, which did slow the game down an annoying amount. Easy to fix that by pairing a more complex hero with a less complex one, though.

Hmm, Tabletop Sim? ;)

If you are talking digital, then I recommend the season 1 pass. It will get you Rook City, Infernal Relics, Shattered Timelines, Wrath of the Cosmos, and the first 3 mini packs. Those are the expansions that expand on the core game, while the second season adds new game modes in addition to heroes and environments. If you instead want individual expansions then that depends on the kind of player you are.

If you are interested in a difficult challenge, I recommend Rook City. It has 3 of the hardest villains in the game and has one of the roughest environments.

If you are interested in interesting and well designed villains, I recommend Infernal Relics, which has 2 of what I consider the best villains in the game.

If you are interested in complicated heroes to learn, Infernal Relics has that too.

If you are looking for interesting environments then I would actually recommend Villains of the Multiverse, though that is from season 2 and won't give you new heroes or classic mode villains.

If none of these interest you then I would just say pick any expansion from season 1, listed at the top, since each will give you some heroes, some villains, and some environments. Of course you can ignore anything I said above, but I implore you, do not get OblivAeon first. That mode takes getting used to even for very experienced players.

I'll disagree with you there and say Season 2, in my opinion, is a better bet.  Rook City (Season 1) is my least favorite expansion (counting Villains, Heroes, and Environments), whereas Vengeance (Season 2) is my favorite -- best heroes, best environments, and great new playstyle.

*edit to add:  Also, Season 1 decks are easily manageable single player on Table Top.  Season 2 is way easier to manage on digital.