i liked the first one for the turnbased strategy and was at first disappointed to read this is a side scrolling shooter but the rpg elements won out. excellent art and deep combat system, fun choices in terms of beast, stats and items both equippable and consumable.
some tips for any1 trying this the first time: autoattacking is much better than manual. when you collide with enemies or get disabled, it's hard to tell when to click again to start attacking. there is no need to try it on nightmare mode first, you can pass the game on pleasant or lucid and keep your items and stats while resetting to lvl 1 (to add even more to your stats) when you transfer to nightmare mode.
for nera i stop adding points to agil at 26 even though its her primary stat, relying on the beezlebub beast (ladon level 5, all azure/black) mirage boots and zodiac master (found in infinity space) items to max her dodge at 85. use her close range attack to clear weak monsters, sometimes her ranged attack for certain bosses.
as sisily, i think her best beast is the behemoth, salamander lvl 5, all crimson/white. i like dragon heart item and cant go wrong with a zodiac master.
i havent done gelyan as much but i like the hydra beast on him, 3 azure/black 1 crimson/white. salamander counts as 1 crimson/white, ladon counts as 1 azure/black