Oh, for a computer game it's quite okay -- though Drakensang is extremely linear, to the point that you can't return to an area once you left it. Also it is very possible to paint yourself in a corner, for instance if you get hurt in an area where you can't get healing and can't get out before you solve the quest --> dead end.
Anyway, basically it works fine as a CRPG system because you don't have to roll yourself.
Tips for your game:
Don't use shields.
When skilling your characters, you should be aware of the very peculiar skill system of TDE. You roll 3 ability checks (for instance on Courage, Intuition and Agility) and use your skill points to balance any botched rolls. For instance if your Courage is 14 but you roll a 17, you need 3 skill points to still make the check. Any remaining skill points after balancing your rolls improve the result. However, check _penalties_ are applied to _each_ of your attributes.
Having to "roll under" three times in a row makes for a very weird, nearly unpredictable probability curve. For instance, the odds to roll under 13 (which is considered "good" as attribute values go) three times in a row without points to balance is just 21%.
What this means in practice is that you should try to get at least 6 ranks in every skill that you plan to use. Once a skill exceeds 10 or 12 ranks, it's almost impossible to fail.
Drakensang is also in some respects decidedly better than the pen&paper system, for instance because they nixed all the useless skills. In TDE, you normally have hundreds of skills, down to useless crap like Farming or Masonry.
The biggest problem of the system however is that it tries to simulate every smallest factor in a "realistic" way. There are actually instances of rules that have been officially replaced by five times more complicated ones just because with the new rule the respective modifier _might_ be one point different in certain cases. As the saying goes, the system is a lot of effort for very little effect.
Likewise, the combat system is awefully complicated, with about a hundred different weapons that all are the _tiniest bit_ different, for instance one might have a -1 initiative penalty and the other does not, or one gives you one extra point of damage for every 3 Strength points above 15 while the other gives you an extra point of damage for every 4 Strength points above 14. Notice something? Considering that it's nigh-impossible for a mortal human in TDE to increase _any_ stat beyond 18 or 20, this "new and improved" damage bonus rule is utter ass-wipe. It goes on like this; there are 3 or 4 different "Reach Classes" that can vary depending on the skill with which you use a particular weapon, and so forth.
Armour carries an Encumbrance Penalty and there is no Armour Proficiency in the sense of D20, so you have to split the ACP evenly and deduct that amount from your Attack and Parry scores.
Note that Shields also have Encumbrance, effectively negating the Parry bonus while gimping your Attack right into the basement.
But on the other hand, each weapon skill (Swords, Maces etc.) has an "Effective Encumbrance" that allows you to ignore 1-3 points of the Armour Encumbrance. And there is a whole stack of armours that have lower Encumbrance than Protection scores. So by choosing the right armour and right weapon, you can effectively ignore most of the Encumbrance, or at worst take a -1 penalty to Attack and/or Parry while enjoying the benefits of DR8. All that fiddling and headache just for a stupid -1 penalty!
Another TDE inadequacy is the actual combat sequence itself, featuring not only active defense (which in itself doubles the time required for each attack), but more importantly the Attack and Parry rolls are _completely detached from each other_. It's not an opposed check, so no matter how well you roll your attack, even the most threadbare Parry will negate your hit. For instance, if two duelists each have Attack and Parry 15, the chance for a successful hit is just under 20% each time.
So every fifth strike hits, and then you roll damage (weapon damage is typically around 1d6+4) and deduct the target's DR, which can, as stated above, very easily reach 7 points. So every _hit_ will on average do about 1 point of damage. That's 0.2 damage per round. Now go figure how long a fight between two 40HP-characters will take.
But the whole system breaks down immediately as soon as two or more attackers gang up on a single defender. Since each Parry takes an Action and you only have two Actions per round, he simply can't defend at least one attack per round. If you ever get into such a situation, kiss your character good-bye and load the character generation program on your computer. Because oh, I think I haven't mentioned it, character creation is so friggin complicated (the skill purchase list alone is a table of about 300 cells) that you WILL need a computer if you want to do it correctly.
So yeah, well, sorry for the rant but those are _some_ of the inadequacies of the Dark Eye system.