It's not bad; it's just not good.
First of all: about the shop. I don't think it took much out of the game so I won't rate lower for its existence. However, I do feel that straight up upgrades are not the way to go for "premium content". What you're basically doing is allowing players to ramp down the difficulty at the cost of some money. You're taking out a level of strategy that had existed without the shop. It could be even be argued that paying for the items makes the game less fun.
Instead, it would've been better if players could pay for "sidegrades". For instance, a player could choose to upgrade one of his skills or spells to a more specialized version. This specialized upgrade may be more useful in certain situations and the player would have to decide before each level whether to use this or the original skill / spell. Of course, for this to work, the player would need some information about the enemies ahead of time but that's a minor detail. With premium content, your goal is to provide the player with more to play with, not less.
My other major complaint is about the control scheme. Firstly, spacebar should never be bound to an action that a player may repeatedly use during the game. It's much easier to tap a letter key than the spacebar. As such, the spacebar should be reserved for single use actions, such as advancing the text, interacting with NPCs, or firing a single shot clearing weapon.
Also, much like the spacebar, number keys should be used sparingly. The main problem is that they are not clustered in one place, unless you expect the player to use the numpad and control the character with only 1 hand. It's best to treat number keys as simply another row of letters. Using number keys means moving one hand away from its controls every time you need to cast a spell or whatever. You might as well assign spellcasting to the left mouse button.
Still a decent game overall. Hope to see more from you guys soon.
