Suoriuduin hyvin, vaikka tehtävä oli vaikea.

Suoriuduin is the 1st person singular past tense form of the verb suoriutua.

So:

• suoriutua = to manage, to get through, to perform, to cope successfully
• suoriuduin = I managed / I did / I got through

In this sentence, it has the sense of I did well or I performed well.

A useful pattern is:

• suoriutua hyvin = to do well
• suoriutua huonosti = to do poorly

This verb often refers to managing a task, challenge, or situation successfully.

Finnish usually does not need a subject pronoun when the verb ending already shows who is doing the action.

Here, -in marks 1st person singular past, so suoriuduin already means I managed / I did.

You can say minä suoriuduin, but it is usually only used for emphasis, contrast, or clarity.

For example:

• Suoriuduin hyvin. = I did well.
• Minä suoriuduin hyvin. = I did well. (emphatic)

This is because Finnish verbs often change shape when they are conjugated.

The dictionary form is suoriutua, but when you remove the infinitive ending -a/-ä, the stem used in conjugation is not simply suoriutu-. In actual forms, it becomes suoriudu- in many contexts:

• suoriudun = I manage
• suoriuduit = you managed
• suoriuduin = I managed

So this is just part of how this verb is inflected. It is something learners usually need to get used to verb by verb.

Hyvin is an adverb, meaning well.

Compare:

• hyvä = good (adjective)
• hyvin = well (adverb)

Because it describes how the action happened, Finnish uses the adverb:

• Suoriuduin hyvin. = I did well.

If you used hyvä, it would not fit here, because hyvä describes nouns, not verbs.

Examples:

• hyvä kirja = a good book
• puhun hyvin = I speak well

Vaikka means although, even though, or though.

It introduces a contrast:

• Suoriuduin hyvin = I did well
• vaikka tehtävä oli vaikea = even though the task was difficult

So the sentence expresses a result that happened despite a difficulty.

Not very much. Finnish word order is generally more flexible than English, but after vaikka, the clause often keeps a normal basic order:

• tehtävä = subject
• oli = was
• vaikea = difficult

So:

• vaikka tehtävä oli vaikea

is a very natural, straightforward clause.

You could move parts around for emphasis in some contexts, but the standard version here is the most neutral one.

Here tehtävä is the subject of the clause tehtävä oli vaikea.

Because it is the subject in a normal affirmative sentence, it appears in the nominative singular:

• tehtävä = the task / assignment / exercise

Compare:

• tehtävä oli vaikea = the task was difficult

If it were an object or part of another structure, it might appear in another case, but here nominative is exactly what you would expect.

Because vaikea is a predicate adjective after the verb oli (was), and it agrees with the subject in the basic nominative form in this type of sentence.

So:

• tehtävä = subject, nominative singular
• oli vaikea = was difficult

This is similar to:

• Talo on suuri. = The house is big.
• Kirja oli mielenkiintoinen. = The book was interesting.

You would not use vaikeaa here, because that form would suggest a different grammatical role.

It can mean any of those depending on context.

Common possibilities:

• task
• assignment
• exercise
• problem (in some contexts)

Without more context, task is a good general translation. In a school context, it might be assignment or exercise.

Oli is the 3rd person singular past tense of olla (to be).

Since tehtävä is singular, the verb is singular too:

• tehtävä oli vaikea = the task was difficult

Compare:

• tehtävät olivat vaikeita = the tasks were difficult

So oli simply matches the singular subject tehtävä.

Yes. Finnish allows that very naturally.

You could also say:

• Vaikka tehtävä oli vaikea, suoriuduin hyvin.

This means the same thing: Although the task was difficult, I did well.

The difference is mainly one of emphasis and flow:

• Suoriuduin hyvin, vaikka tehtävä oli vaikea.
  Starts with the main result.
• Vaikka tehtävä oli vaikea, suoriuduin hyvin.
  Starts with the difficulty, then gives the result.

Both are correct and natural.

It is not reflexive in the same way as, for example, English myself constructions. But it is a verb that behaves a bit differently from simple basic verbs like tehdä or puhua.

The important thing for learners is that suoriutua is an intransitive verb often used with the idea of managing or coping with something.

Very often it can also appear with an elative complement:

• suoriutua tehtävästä = to manage the task / to get through the task

But in your sentence, that complement is not included. The sentence simply says:

• Suoriuduin hyvin = I did well

So you do not need to treat it as reflexive; it is better to learn it as its own verb pattern.

Not usually in the same sense.

Tehdä means to do/make, but tein hyvin by itself usually does not mean I did well in the same natural way that English does.

Finnish normally uses expressions like:

• suoriuduin hyvin = I did well
• pärjäsin hyvin = I managed well
• onnistuin hyvin = I succeeded / did well

So suoriuduin hyvin is a very natural choice here, while tein hyvin would usually sound incomplete or mean something else depending on context.

A few natural alternatives are:

• Pärjäsin hyvin, vaikka tehtävä oli vaikea.
  = I managed well, even though the task was difficult.

• Onnistuin hyvin, vaikka tehtävä oli vaikea.
  = I succeeded / did well, even though the task was difficult.

• Tehtävä oli vaikea, mutta suoriuduin hyvin.
  = The task was difficult, but I did well.

These are not always identical in nuance:

• suoriutua focuses on performance or handling the task
• pärjätä focuses on coping/managing
• onnistua focuses on succeeding

But all can be close depending on context.