The Pleasure Forest in Sagami lake

My old company ended yesterday and has just merged an another company today.My old company ended yesterday and merged with another company today.

The company name has changed from the before so today is birthday and death-day of our company.The company name has changed, so today is the birth-day and death-day of our company.

This was the last event of my previous company.(I'm not sure that this 'previous' is correct because my company is present by different name.) This was the last event of the company.

If it is still the same company, but with a different name, being more vague and saying 'the company' makes sense in context with the previous sentences.

This event concluded the farewell party about the company and one colleague who leaves our company at same time of that our previous company has ended.This event concluded the farewell party for the company and one of my colleges who is also leaving.

My daughter also seemed to be happy because she played much with my colleague's daughters.My daughter seemed happy because she played a lot with my colleagues' daughters.

Of course I played with them, especially water gun playing was very fun but very tired.Of course, I played with them as well, especially the water gun games, which were very fun but very tiring.

Although it's Sunday today, I'm in new office(it's wordplay only, it's just ordinal room.)Even though it's Sunday today, I'm in my new office (it's wordplay only, it's just an ordinary room.)