My rating: **** (four out of five stars)
You'll have to grind (and die) like crazy to get anywhere in this game!
This is an excellent old-school arcade-ish action-platformer with stellar production values and great (but difficult) gameplay. You've read the other reviews (I assume), so I'll just add a few thoughts (and gripes).
This is indeed about as high-quality as you can get from a "retro-style" game, and it has a great gimmick in the "descendants" feature (leaving your loot to your heirs after you die. The sense of humor is great, with an old-school vibe that clearly is inspired by the old Capcom arcade game "Ghosts & Goblins."
The reason I don't give it a full five stars is that it is way too grindy! It seems that you'll have to play for days on end to get powerful enough to reach the further areas on the map! Usually, you'll die in the first regions of the map (even with powerful gear), meaning you'll see the same regions over and over and over. I felt I wasn't getting anywhere after 19 hours (as of this writing) of playtime. I have decent action/arcade skills, but I just kind of gave up.... for now. I'm sure I'll come back to it later.
Still, it was 19 hours of great fun, especially for the price I paid. It's worth giving "Rogue Legacy" a shot if you like "Ghosts and Goblins" style gameplay... perhaps you'll get further than I did!