Fill-in-the-blanks with variable scoring - possible?

Hello all,

I am having an issue trying to find the most effective solution for a variable scoring requirement.

What we want to happen is the following:

A user is presented with a (partially obscured) logo. The aim is for them to correctly identify the logo and type the correct answer into a text field.

If they do this (spelt correctly, and without using 'hints') then they would be awarded the maximum 3 points.

If they need a hint (which reveals more of the logo), it would deduct a point each time, to a minimum of 1.

If they type the wrong answer, or misspell it, this would also deduct a point, down to a minimum of 1.

Since the user has to answer this question correctly to proceed (and the answer will be obvious by the time they have used the hints anyway), we wish to still award them 1 point out of a possible 3, even if they have used all the hints and made multiple attempts at answering before they get it.

I have tried looking at this using a Freeform text entry question slide - while the visual side of things is easy enough to figure out, the validation and scoring are more problematic.

Does anyone know if there is a way to use a trigger with the answer validation process? ie; if they get it wrong/right, it activates a trigger which will do our custom scoring?

It would be nice to be able to use the Freeform text entry question as well, because if we do our own custom validation on the text they enter, it will involve many, many conditionals as there are a number of spellings/acceptable answers.

Any help would be much appreciated!