PEBKAC (problem exists between keyboard and chair) rings true the more I read chat in Devilian with regards to how some players (coming from Diablo III) are having a difficult time with the controls as well as animation lock, and end up deeming the game play as clunky or frustrating.
Devilian is more of a hybrid of both ARPG and MMO and some of its game play design reflects that once you begin doing more and more difficult content in the game. The early parts of the game are deceptively too simple and easy (like by the time you enter the first town (Adeline Coast), you are already level 5 or 6 after face rolling the initial opening encounters.
D3 takes almost zero keyboard and mouse dexterity to play (you can spam mouse and keyboard clicks) whereas in Devilian, it makes a world of difference by separating out your movement abilities from your mouse clicks. You cannot just spam in Devilian because you have to make a conscious decision (once you commit, you cannot cancel – thus the other perceived issue with animation lock which the producer of Devilian said was a conscious design).
The game can still be played the way most isometric ARPG’s work but you lose a whole lot of targeting precision in the process when you should be moving, targeting, and firing off skills at the same time in Devilian. Same goes for other details like with penetration (similar to piercing ability in D3) as one simple example. It’s both a positive and negative in Devilian because certain skills with range can penetrate fairly far and thus aggro monsters further away in the process. The game play in Devilian can be deliberate at times and is similar to the kind of real time decisions required when playing something like Dark Souls (where your actions and decisions matter).
A multi-button gaming mouse and/or gaming pad like a Nostromo can help (you just need to program it to the available keybindings that you set in the game) for those who are more hardcore oriented and take their controls seriously (I’ve tried just playing with the keyboard and it isn’t the best way due to the amount of available skills that you can use; it’s much better mapping some of them to a gaming mouse and/or something like a Nostromo). In my case, I use a Logitech G502 Proteus Core and Razer Nostromo.
To put it even more bluntly, Devilian at end game does take more player skill to master compared to Diablo III, Torchlight, and even Path of Exile in terms of game play controls. D3 out of all these is the most easiest to play though even at end game because its been mostly designed to be that way.