Yeah, Lego Marvel is good & I'd say it's a platformer. Has a lot of platforming in it at any rate.
As for must-have games, I think everyone should at least play Warframe. It's free and it's incredible - there's no harm in trying it, but know going in that there IS a learning curve. It's not a game you can play for 30 mins & make a snap judgement on. Basically, the game is what would happen if a 3rd-person shooter had a baby with Phantasy Star Online. The dev is fantastic about supporting it as well, really listens to the community and has made what I consider to be the blueprint for how free to play games should be done. If anyone tells you the game requires microtransaction or is a "pay to win" game then that person does NOT understand the game. The only things you have to pay actual money for are either cosmetic or expansion slots to hold more weapons & frames later on (and you won't need those for a while - when you do, they're inexpensive and by that point you'll probably WANT to give the dev some cash for making such an awesome game
).
I gush about that game because I truly love it, it was my GOTY last year. I've logged somewhere in the neighborhood of 250 hours into it and I still find it incredibly fun & addictive.
tl;dr - Warframe is a free download that everyone should at least try because you have nothing to lose.