Stella Deus is pretty much unplayable, honestly. It has a nice aesthetic (it's basically P2 but PS2 quality), but uuuurgh actually playing it a chore. Attack animations take forever (you can't turn them off!), there's only a handful of enemy types so you're pretty much facing the same things over and over and over, accuracy is modified way, way too heavily by level difference (ie if you aren't at least the same level as your target you're pretty much just going to be swatting at it and only landing one attack for every five you attempt), and the item fusion system has no internal consistency (like in Persona, ok, you can look at a fusion chart and see that a Hierophant Persona x a Death Persona will yield whatever, but in SD it's like, Leather Hat + Short Knife = Scale Armor, Leather Hat + Long Knife = Elixir, Leather Hat + Kitchen Knife = Leather Boots).
It's not worth five bucks unless you just really, really, really want to see Soejima's artwork on PS2-quality hardware or if you just really have to see Soejima drawing nipples and giant boobs.