Not really much like shin megami... more like dragon quest monsters. Very much like DQM, since siralim's basically its random dungeons taken to another level, as a game. It* has its limitations, but overall they're pretty ruddy good at what they set out to do. Good stuff, particularly so long as you're not expecting
more than what the game sets out to do. Pretty sure there's dedicated threads for both of them sleeping somewhere a ways back in Other Games (and by pretty sure I mean I started one of them

).
There's demo/free versions both on mobile and PC, iirc... might not be for 2, but definitely is for 1. If you're interested but hesitant, check that out first. While the full versions (and particularly 2) are more and better than the free stuff, the free stuff gives you a very solid idea of how the general game plays out.
Though just to reiterate, if you're going to put money in it, get the sequel. Siralim 2 improves on pretty literally every feature of siralim 1, and adds more besides.
* I use singular because the sequel is better in literally every way; siralim 1 might as well not exist at this point, heh. There's zero reason to get 1 besides not being able to afford 2.