Hello, first I would like to point put that I had much fun with your games, ES1 and ES2 as well. I have even considered buying the new DLC for ES2. Until I found out that in order to access all game features, I must connect my Steam account with this page which I visited twice to ask for a help with bugs or very problematic quest design.

I am sorry, but in today's world where even CPUs are not secure anymore I will not give my credentials to ANYONE. I do not see a single reason why you, or anyone else, should know my Steam log in details. Especially when a friend of mine got his Steam account stolen two weeks ago and had to spend whole day with Steam support to get it back. This discovery fed me up so much that I am even considering contacting Steam for a refund as there is not a single word about having to give my credentials to a third party in order to access all game features. Maybe it is in EULA but since EULA is not in Czech language, it is not valid (bless customer protection laws). And before you start with the cliche that other companies do it also, I do not give a damn about other companies. None of my ohter games requires such a breach of privacy.

I will wait a few days for you to reconsider and to release all the stuff as a simple free DLC. But if there is not a change, I will ask Steam support for a refund.

=D

I'll give you that If this is a troll post you got me laughing good but If not, calm down! They are not getting your Steam Credentials. You are logging though steams official page. Many third party can use this and doesn't mean they are getting access to your Steam Information (well maybe only to your steam id but It is a public information anyway). Your "credentials" are still safe in Steam data they are not sharing with anyone. It's just a thing they are doing to promote people coming here, growing community. 

Valve build an awesome API, and now people feakout and blame Amplitude for Valve's feature...

So you took who know how much time to write this but did you ever even bother to read the actual text when a website sends you to steam's account connection page?

Here's the text for signing into backpack.tf:

By signing into backpack.tf through Steam:

• Your Steam login credentials will not be shared.
• A unique numeric identifier will be shared with backpack.tf. Through this, backpack.tf will be able to identify your Steam community profile and access information about your Steam account according to your Profile Privacy Settings.
• Any information on your Steam Profile page that is set to be publicly viewable may be accessed by backpack.tf.

By clicking "Sign In" you agree to this data being shared.

notice the second line:

• Your Steam login credentials will not be shared.

most likely your friend just got hacked since they didn't use 2-factor auth...